Modulation and multiplexing in Optical Communication Systems · 2016-11-22 · Frequency WDM...

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IEEE

THE SOCIETY FOR PHOTONICS

NEWS

February 2009Vol. 23, No. 1www.i-LEOS.org

Optical Communication Systems

Modulation andmultiplexing in

February 2009 IEEE LEOS NEWSLETTER 1

February 2009 Volume 23, Number 1

COLUMNS

Editor’s Column. . . . . . . . . . . 2 President’s Column . . . . . . . . . . . 3

DEPARTMENTS

News . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262009 IEEE/LEOS Fellows• 2009 IEEE/LEOS Award Reminders: William Streifer Scientific • Achievement Award, Engineering Achievement Award, Aron Kressel Award, and Distinguished Service AwardCall for Fellow Nominations• Nomination Form for IEEE/LEOS Awards•

Careers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302008 LEOS Student Paper Award Recipients• 2009 IEEE/LEOS Young Investigator Award Recipient: Aydogan Ozcan• 2009 IEEE David Sarnoff Award Recipients: Yasuhiko Arakawa, • Kerry John Vahala, and Kam Yin Lau

Membership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Chapter Highlight: Italy Chapter• Benefits of IEEE Senior Membership• New Senior Members•

Conferences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362008 LEOS Awards and Recognition• “International Conference on Advanced Optoelectronics and • Lasers” by Igor A. Sukhoivanov20th Annual Workshop on Interconnections Within High Speed • Digital Systems – 2009The Optical Data Storage Topical Meeting – 2009• IPRM – 2009• IEEE/LEOS International Conference on Optical MEMS & • Nanophotonics – 2009

Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47Call for Papers:•

IEEE Journal of Selected Topics in Quantum Electronics (JSTQE) –

FEATURES

Research Highlights: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 “Modulation and Multiplexing in Optical Communication Systems,” –

by Peter J. Winzer“Electronic Signal Processing for Fiber-Optic Communications,” by John Cartledge et al –“Radio over Fiber Distributed Antenna Networks,” –

by Michael J. Crisp et al“Enabling Microwave Photonic Technologies for Antenna Remoting,” –

by Dalma Novak

Page 6, Fig. 4. Orthogonality through disjoint frequency bins (WDM) can be combined with orthogonality in the polarization dimension.

22

17

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3GHUB WLAN

2 IEEE LEOS NEWSLETTER February 2009

Editor’sColumnKRISHNAN PARAMESWARAN

Welcome to the first LEOS Newsletter of 2009! Last year was tumultuous in many respects through-

out the world. The Photonics industry will certainly play a positive role in the eventual economic revival. As most of you know, LEOS will change its name to the IEEE Photonics Society this year. This name change certainly reflects the focus of those who work in our field − let us hope that it signals the start of a successful year for our field and the economy as a whole!

We have four feature articles this month, all with the general theme of optical communications. Two articles focus on optical fiber systems. Peter Winzer of Bell Labs describes modulation and multiplexing formats, and John Cartledge and colleagues at Queen’s University and Nortel Networks in Canada have written a nice piece on electronic signal processing for fiber communications. The other two articles discuss antenna networks. Michael Crisp and co-workers at the University of Cambridge discuss radio-over-fiber distributed antenna networks, while Dalma Novak of Pharad discusses microwave photonic technology.

In Membership News, chair of the LEOS Italian Chapter (2008 LEOS and IEEE Region 8 chapter of the year) Tiziana Tambosso has contributed an article describ-ing activities in the Italian LEOS Chapter. The breadth of activities there should inspire all of us to get involved in our local sections. Finally, we have a nice piece from Prof. Igor Sukhoivanov of the Ukraine Chapter describ-ing a conference held there last fall.

As always, please feel free to send any comments and suggestions to [email protected]. I would love to hear what you would like to see in the Newsletter this year. I wish everyone a happy and prosperous 2009!

Regards,Krishnan Parameswaran

PresidentJohn H. MarshDept of E & E EngineeringRankine BuildingUniversity of GlasgowGlasgow G12 8LT, Scotland, UK.Tel: +44 141 330 4901Fax: +44 141 330 4907E-mail: [email protected]

President-ElectJames ColemanDept. of E & C EngineeringUniversity of Illinois208 N Wright StreetUrbana, IL 61801-2355Tel: +1 217 333 2555E-mail: [email protected]

Past-PresidentAlan WillnerUniversity of Southern CaliforniaDept. of EE-Systems/Rm EEB 538Los Angeles, CA 90089-2565Tel: +1 213 740 4664Fax: +1 213 740 8729Email: [email protected]

Secretary-TreasurerJerry MeyerNaval Research LaboratoryCode 5613Washington, DC 20375-0001Tel: +1 202 767 3276E-mail: [email protected]

Executive DirectorRichard LinkeIEEE/LEOS445 Hoes LanePiscataway, NJ 08855-1331Tel: +1 732 562 3891Fax: +1 732 562 8434Email: [email protected]

Board of GovernorsS. L. Chuang C. GmachlK. Hotate J. JackelJ. Kash T. KoonenM. Lipson J. MeyerD. Plant A. SeedsP. Winzer I. White

Vice PresidentsConferences - D. RabusFinance & Administration - F. Bartoli

Membership & Regional Activities - A. HelmyPublications - R. TuckerTechnical Affairs - A. Seeds

Newsletter Staff

Executive EditorKrishnan R. Parameswaran Physical Sciences Inc.20 New England Business CenterAndover, MA 01810Tel: +1 978 738 8187Email: [email protected]

Associate Editor of Asia & PacificHon TsangDept. of Electronic EngineeringThe Chinese University of Hong KongShatin, Hong KongTel: +852 260 98254Fax: +852 260 35558Email: [email protected]

Associate Editor of CanadaLawrence R. ChenDepartment of Electrical & Computer EngineeringMcConnell Engineering Building,Rm 633McGill University3480 University St.Montreal, QuebecCanada H3A-2A7Tel: +514 398 1879Fax: 514-398-3127Email: [email protected]

Associate Editor of Europe/Mid East/AfricaKevin A. WilliamsEindhoven University of TechnologyInter-University Research Institute COBRA on Communication TechnologyDepartment of Electrical EngineeringPO Box 5135600 MB Eindhoven, The NetherlandsEmail: [email protected]

Staff EditorGiselle BlandinIEEE/LEOS445 Hoes LanePiscataway, NJ 08855-1331Tel: +1 732 981 3405Fax: +1 732 562 8434Email: [email protected]

IEEE Lasers and Electro-Optics Society

LEOS Newsletter is published bimonthly by the Lasers and Electro-Optics Society of the Institute of Electrical and Electronics Engineers, Inc., Corporate Office: 3 Park Avenue, 17th Floor, New York, NY 10017-2394. Printed in the USA. One dollar per member per year is included in the Society fee for each member of the Lasers and Electro-Optics Society. Periodicals postage paid at New York, NY and at additional mailing offices. Postmaster: Send address changes to LEOS Newsletter, IEEE, 445 Hoes Lane, Piscataway, NJ 08854.

Copyright © 2009 by IEEE: Permission to copy without fee all or part of any material without a copyright notice is granted pro-vided that the copies are not made or distributed for direct com-mercial advantage, and the title of the publication and its date appear on each copy. To copy material with a copyright notice requires specific permission. Please direct all inquiries or requests to IEEE Copyrights Office.


President’sColumnJOHN H. MARSH

I would like to start by wishing you all a (belated by the time it reaches you) Happy New Year. The New Year is traditionally a time for renewal and change, and 2009 will certainly see many changes for the Society.

A new nameAs you will be aware, we have recently addressed the name of the Society, and whether a new name would better describe the field of interest or would assist the Society in realizing its vision.

The Society’s field of interest is:‘lasers, optical devices, optical fibers, and associated lightwave

technology and their applications in systems and subsystems in which quantum electronic devices are key elements’,

and the vision for the Society is:‘to be the primary forum where critical and fundamental advances

in the field are shared, nurtured and coupled to developments in related disciplines’.

The membership survey conducted last year demonstrated overwhelming support for changing the name of the Society. Key results from the survey are as follows:

38% of members and 15% of non-members participated• 82% of respondents said • Photonics represents their work well, compared to 52% for LEOS75% of respondents said • Photonics would be well-understood by those not in the field, compared to only 22% for LEOS74% of respondents indicated that the • IEEE Photonics Society would better represent the activities of the Society than IEEE-LEOS.Given the high level of participation and the clear responses

from the survey, the Board of Governors voted unanimously for a change in the name of the Society. At the IEEE Meeting Series in November, I presented a motion for the change in name to the IEEE Society Presidents’ Forum which gave its unanimous support – the results of the survey being a clear fac-tor in gaining this approval. The following day, the full IEEE Technical Activities Board also gave its unanimous approval.

Any change to the Society’s Constitution also requires a membership consultation, followed by a ballot if more than 5% of the membership requests this. The consultation period ended on 30th December, and I am pleased to inform you that there have been no requests for a ballot, and only one member has indicated unhappiness with the change.

One of the most striking changes that will therefore happen in 2009 is that LEOS will become the IEEE Photonics Society. The new name now has approval and support from the Board of Governors, the IEEE Technical Activities Board and, most importantly, the membership. The remaining step is formal approval by the IEEE Board of Directors, which is expected in February. The new name will be introduced thereafter.

On an issue as sensitive as the name of the Society, there will always be a divergence of views. In particular, there is affection

for and familiarity with the existing name, and LEOS does have strong brand recognition within the field. However, the ques-tions are whether the new name better describes the field in which we work, and whether it will better enable to us to realize the Society’s vision. The results of the membership survey are very clear. Moreover, this is not the first time the Society has changed its name – it was first founded as QEAS (the Quan-tum Electronics and Applications Society), before adopting the name LEOS.

I personally believe the IEEE Photonics Society will be much more widely recognized than LEOS. Even within IEEE – even within TAB itself with its 38 Societies and 7 Technical Councils – the LEOS acronym is not universally recognized! The societies that are well recognized usually have single word names – Com-puter, Communications, Reliability, Education – and are known by these names rather than by a collection of letters (though the Communications Society is generally known as ComSoc). These names also have meanings understood throughout the engineer-ing and scientific professions, and, significantly, by the wider public. Photonics is a single word that encompasses the field of our Society, and adopting this name gives us the opportunity to be more widely recognized and to be more effective in outreach.

Changes in the society leadershipEntering 2009, there are significant changes to the Society leadership. We have a new President-Elect and several Vice-Presidents have retired.

I am delighted to inform you that James Coleman (Univer-sity of Illinois) was chosen as President-Elect at the November BoG meeting. He will become President in January 2010.

The new Vice-Presidents are:Conferences Dominik Rabus (Buerkert • Werke GmbH, Germany)Finance and Administration Fil Bartoli (Lehigh • University, Pennsylvania)Publications Rod Tucker (University • of Melbourne, Australia)Secretary/Treasurer Jerry Meyer (Naval • Research Laboratory, DC)Amr Helmy (University of Toronto, Canada) and Alwyn Seeds

(UCL, United Kingdom) continue to serve as VP Membership and Region Affairs and VP Technical Activities respectively.

I would like to thank the retiring VPs for their tireless work for the Society over the last three years – Katya Golovchenko (Conferences), Steve Newton (Finance and Administration), Fil Bartoli (Secretary/Treasurer).

I would also like to thank Carmen Menoni, who retired from Publications after only two years so she could take up the post of Editor in Chief of the new IEEE Photonics Journal. There will

(continued on page 25)


Research Highlights

Modulation and multiplexingin optical communication systemsPeter J. Winzer

Digital electronics and optical transportThe rapid transition from analog to digital systems over the past ~50 years has enabled universal processing of all kinds of informa-tion, fundamentally without loss of quality [1]. Breakthroughs in digital semiconductor technologies and their enormous abil-ity to scale [2] have enabled cost-effective mass-production of richly functional yet highly reliable and power-efficient micro-chips that are found in virtually any electronic device today, from high-end internet routers to low-end consumer electronics.

Closely coupled to the generation, processing, and storage of digital information is the need for data transport, ranging from short on-chip [3] and board-level [4,5] data buses all the way to long-haul transport networks spanning the globe [6,7] and to deep-space probes collecting scientific data [8], cf. Fig. 1 [5,10]. Each of these very different applications brings its own set of technical challenges, which can be addressed using elec-tronic, radio-frequency (RF), or optical communication systems. Among the different communication technologies, optical com-munications generally has the edge over baseband electronic or RF transmission systems whenever high aggregate bit rates and/or long transmission distances are involved. Both advantages are deep-ly rooted in physics: First, the high optical carrier frequencies allow for high-capacity systems at small relative bandwidths. For example, a mere 2.5% bandwidth at a carrier frequency of 193 THz (1.55 µm wavelength) opens up a 5-THz chunk of continuous communication bandwidth. Such “narrow-band” systems are much easier to design than systems with a large rela-tive bandwidth. Second, transmission losses at optical frequen-cies are usually very small compared to baseband electronic or RF technologies. Today’s optical telecommunication fibers exhibit losses of less than 0.2 dB/km; the loss of typical coaxial cables supporting ~1 GHz of bandwidth is 2 to 3 orders of magnitude

higher. In free-space systems optical beams have much smaller divergence angles than in the microwave regime1, at the expense of significantly exacerbated antenna pointing requirements, though. The narrow beam width favorably translates into the system’s link budget, in particular in space-based systems where atmospheric absorption is less of a problem. Apart from the above two major advantages, other considerations sometimes come into play, such as the unregulated spectrum in the optical regime or the absence of electromagnetic interference.

The gradual replacement of electronic transportThe suitability of optical communications for different sys-tem scenarios can be further analyzed using the three basic transponder characteristics shown in Fig. 2: A transponder’s sensitivity measures the minimum power (or the minimum signal-to-noise ratio) required by the receiver to close a digi-tal communication link, which impacts the link distance that may be bridged. In this loosely defined context, the term “sen-sitivity” also includes the effect of linear and nonlinear signal distortions due to the transmission channel. The capacity of a system measures the amount of data that can be transmit-ted over the communication medium. Here, we think of the capacity per waveguide, with the understanding that parallel lanes (buses) are likely to be used in applications that require high aggregate capacities at tight transponder integration re-quirements. In many applications, implementation aspects of a transponder (including its physical dimensions, power con-sumption, cost, and reliability) are the most critical param-eters and often delay the entrance of optics into a particular application space. The figure roughly indicates the relative

1 The divergence angle of an antenna of diameter D operating at wavelength l is given by l/D. At 1µm, a telescope (=antenna) of 10 cm diameter has a divergence angle of 10 µrad (50.6 mdeg).

100,000 km 1,000 km 10 km 100 m 1 m 1 cm

Deep-Space

GEO, LEO

Submarine

Terrestrial Networks

Access

Rack-to-Rack

Backplanes

Chip-to-Chip

On-Chip

Figure 1. Digital communication distances can be over 100,000 km in deep-space missions and below 1 mm on-chip. (GEO: Geostationary satellite orbit; LEO: Low-Earth satellite orbit.) Figures reproduced with permission. From left to right, courtesy of (1) NASA/JPL-Caltech; (2) European Space Agency (ESA); (3) Alcatel-Lucent; (4) Alcatel-Lucent [11]; (5) Corning, Inc. [9]; (6) – (9) IBM [3].

BELL LABS, ALCATEL-LUCENT, HOLMDEL, NJ 07733


importance of the three performance metrics for different com-munication applications.

As bandwidth demands have continuously increased and as opto-electronic device and integration technologies have ad-vanced, optical communications has gradually replaced elec-tronic (and to some extent directional2 microwave) solutions. This process started on a large scale in the late 1970s and 1980s at the most demanding high-bandwidth/long-distance appli-cations of terrestrial [6] and submarine [7] transport. With massive fiber-to-the-home (FTTH) deployments now under-way world-wide, optics is currently capturing the access space [9], and rack-to-rack interconnects are starting to become opti-cal [3]. The red application areas in Fig. 2 indicate well estab-lished optical communication technologies. The applications marked orange denote areas where optics can be found but is not yet used on a massive scale. The blue applications are still dominated by electronics, with research on optical successors being actively pursued. Despite the continuing improvement in electronic transmission techniques [12], optical solutions are expected to enter backplanes, paving the way to optical chip-to-chip and, eventually, on-chip communications once electronic transmission can no longer keep pace with the grow-ing need for communication capacity, power consumption, or “escape bandwidth”, i.e., the interconnect capacity per unit of interface area [3,4,5]. At the same time, areas where optical communications is already well established have to continue supporting ever-increasing capacity demands.

Orthogonal dimensions and multiplexingIn order to meet the application-specific requirements on sen-sitivity and capacity under the respective implementation con-straints, one has to choose the best suited modulation and mul-tiplexing techniques based on the available physical dimensions shown in Fig. 3 [13].

Of particular importance in this context is the notion of orthogonality [15]. Loosely speaking3, two signals are orthogo-nal if messages sent in these two dimensions can be uniquely separated from one another at the receiver without impacting each other’s detection performance. This way, independent bit streams can share a common transmission medium, which is re-ferred to as multiplexing. The amount of individual bit streams that can be packed onto a single transmission medium deter-mines a system’s aggregate capacity. The most advanced multi-plexing techniques are therefore found in capacity-constrained systems, such as long-haul fiber-optic transport (cf. Fig. 2).

Multiplexing is performed by exploiting orthogonality in one or more of the physical dimensions shown in Fig. 3. Sending signals in disjoint frequency bins on different optical carrier frequencies is called wavelength-division multiplexing (WDM), cf. Fig. 4. Such signals are orthogonal, and individ-ual bit streams can be recovered using optical bandpass filters or electronic filters following a coherent receiver front-end

2 Owing to the inherently high directionality of optical antennas, microwave systems will likely continue to be the solution of choice for mobile environments requiring omni-directional reception and transmission.3 A rigorous definition of orthogonality in the context of optical communi-cations is given in, e.g., [13,14].

[16]. If signals leak energy into neighboring frequency bins, orthogonality is degraded and perfect reconstruction is no lon-ger possible (‘WDM crosstalk’). As shown in Fig. 4, a possible counter-measure, which has been used in some research dem-onstrations, is alternating the polarization of adjacent chan-nels to re-establish orthogonality in the polarization dimension (‘polarization interleaving’).

Using true polarization-division multiplexing (PDM, cf. Fig. 4), one sends two independent signals on both orthogonal polar-izations supported by a single-mode optical fiber. In order to recover these polarization-multiplexed bit streams, one either uses a polarization beam splitter whose axes are constantly kept aligned with the signal polarizations (‘polarization control’), or one detects two arbitrary orthogonal polarizations (‘polar-ization diversity’) using coherent detection. Since upon fiber transmission the polarization axes at the receiver will be ran-domly rotated compared to the transmitter, one electronically back-rotates the detected signals using the (estimated) inverse Jones matrix of the transmission channel. This is the approach taken by modern coherent receivers [16].

Another way of achieving orthogonality in the frequency domain is by letting the signal spectra at adjacent wavelengths overlap but choosing the frequency spacing to be exactly 1/T

S, where T

S is the symbol duration, synchronized across the

individual (sub)carriers. This approach is visualized in time and frequency domain in Fig. 5. Although the superposition of the three modulated signals (examples shown are ‘11213’ and ‘12213’) looks unintelligible at a first glance, a receiver can uniquely filter out the information transported by each sub-carrier by first multiplying the superposition with a sine wave of the desired subcarrier’s frequency and then integrating over the symbol duration. This operation can be particularly efficiently done in the electronic domain using the fast Fourier transform (FFT). This kind of multiplexing is known as orthogonal fre-quency division multiplexing (OFDM) [17] or coherent WDM

On-Chip

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Figure 2. Sensitivity, capacity, and implementation aspects (physi-cal dimensions, power consumption, and cost) are key factors be-hind the success of any communication technology. Starting from “high sensitivity / high capacity” applications (terrestrial and sub-marine long-haul), optical communications is steadily replacing electronic transmission technologies.


(CoWDM) [18,19], depending on whether the (de)multiplexing operations are performed electronically or optically (equivalent to the distinction between ETDM and OTDM in the time do-main). If the orthogonal waveforms are not sine waves but or-thogonal sequences of short pulses (“chips”), we arrive at optical code-division multiple access (oCDMA) [20].

Finally, one can make use of the spatial dimension, in its most obvious form by sending different signals on parallel optical waveguides, sometimes referred to as spatial multiplex-ing. Using parallel waveguides is particularly attractive for

implementation-constrained systems (rack-to-rack intercon-nects and shorter), where frequency stable lasers and filters operating over a significant temperature range lead to bulky and power-consuming solutions, and coherent signal process-ing becomes problematic for the same reasons. Here, coarse WDM (CWDM) with uncooled components allows for chan-nel spacings of typically 20 nm and can be an attractive multi-plexing solution. In contrast, for long-haul transport systems, which are the most capacity-constrained systems existing to-day, spatial multiplexing is not cost efficient, and dense WDM is a requirement, recently even in combination with PDM. The key parameter characterizing such systems is the spectral

PolarizationFrequency

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Figure 3. Physical dimensions that can be used for modulation and multiplexing in optical communications. (OTDM: Optical time-division multiplexing; ETDM: Electronic time-division multiplexing; oCDMA: Optical code-division multiple access; PPM: Pulse position modulation; PolSK: Polarization shift keying; FSK: Frequency-shift keying; MSK: Minimum-shift keying; WDM: Wavelength-division multiplexing; CoWDM: Coherent WDM; OFDM: Orthogonal frequency-division multiplexing; PSK: Phase shift keying; QPSK: Quadra-ture PSK; QAM: Quadrature amplitude modulation; E

x: Optical field (x polarization).)

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Figure 4. Orthogonality through disjoint frequency bins (WDM) can be combined with orthogonality in the polarization dimension.

Figure 5. Orthogonal frequency spacings of 1/TS lead to OFDM or

CoWDM.

1/Ts

Ts

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2 3


efficiency (SE), defined as the ratio of per-channel bit rate to WDM channel spacing.

Modulation and codingModulation denotes the method by which digital information is imprinted onto an optical carrier, and in its most general sense also includes coding to prevent transmission errors from occur-ring (‘line coding’) or to correct for already occurred transmis-sion errors (‘error correcting coding’).

Uncoded on/off keying (OOK, cf. Fig. 6) in its various fla-vors [21] has been used in optical communications for decades because it is by far the simplest format in terms of hardware implementation and integration and exhibits a good compro-mise between complexity and performance. Those applications in Fig. 2 that are identified to be implementation-constrained, especially if integration and power efficiency weight heavily, are likely to employ uncoded OOK until capacity or sensitivity requirements dictate the use of more sophisticated formats or computationally intensive error correcting coding.

For sensitivity-dominated applications, in particular for space-based laser communications, binary phase shift keying (PSK, cf. Fig. 6) was studied intensively and set several sen-sitivity records [22,23,24]. Further sensitivity improvements can be obtained at the expense of modulation bandwidth, ei-ther by M-ary orthogonal modulation or by coding.

Orthogonal modulation formats employ M . 2 orthogonal signal dimensions, such as M non-overlapping time slots per symbol duration ( pulse position modulation, PPM, cf. Fig. 6 for M 5 4) [8,14,25] or M orthogonal frequencies (M-ary frequency-shift keying, FSK) [14]. In PPM, an optical pulse is transmitted in one out of M slots per symbol. The occupied slot position de-notes the bit combination conveyed by the symbol. Both PPM and FSK expand the signal bandwidth by M/log

2M compared

to OOK. For example, using 64-PPM, sensitivity is improved by 7.5 dB at a bit error ratio (BER) of 10–16 at the expense of a 10-fold increase in modulation bandwidth [15].

With error correcting coding (‘forward error control’, FEC), redundancy is introduced at the transmitter and is used to correct for detection errors at the receiver [26]. Typical FECs for terres-trial fiber-optic systems today operate at up to 40 Gb/s with 7% overhead and are able to correct a channel BER of of 2 3 10–3 to 10–16, yielding a sensitivity improvement of ~9 dB at a mere 7% bandwidth expansion. FECs with more than 11 dB of coding gain at BER 5 10–16 and at a 25% bandwidth overhead have been implemented at 10 Gb/s [26]. These high sensitivity gains achieved by FEC at a low bandwidth expansion in comparison with orthogonal modulation come at the expense of a signifi-cant increase in implementation complexity for FEC processing. Through the combination of modulation and coding, sensitivi-ties of 1 photon/bit have been reported using PPM [27].

In contrast, capacity-constrained systems employ modula-tion formats that avoid an increase in modulation bandwidth to allow for dense WDM channel packing (high spectral effi-ciency). Narrow modulation spectra are accomplished by stick-ing to the two-dimensional quadrature signal space, i.e., by us-ing multiple levels of real and imaginary parts (or magnitude and phase) of the complex optical field, as shown by the three examples in Fig. 3. In addition, low-overhead FEC (~7% to

~25%) is used to improve sensitivity. At currently investigated 100-Gb/s single-channel rates, quadrature phase shift keying (QPSK) [28,29], 8-PSK [30], and 16-QAM [31] have been reported, both on a single carrier and using CoWDM [32].

Figure 7 visualizes the trade-off between sensitivity and spectral efficiency for the linear additive white Gaussian noise (AWGN) channel4 [15]. The ultimate limit is given by Shannon’s

4 Different limits are obtained for other channels, for example for the shot noise limited case. While the AWGN channel is the most relevant for optically amplified transmission systems [33], free-space systems can be shot-noise limited [25,34].

Inte

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1 0 0 1 1 1 10 0 0

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6432

84

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Sensitivity-Constrained

Capacity-Constrained

OOK

256[35]

[23][36]

[29][30]

[31][37]

[38]128

Figure 6. Waveforms associated with some optical modulation formats.

Figure 7. Trade-off between spectral efficiency (per polarization) and sensitivity of various modulation formats limited by AWGN. Modu-lation formats (bright: theoretical limits; faint: experimental results) are reported for a 7% overhead code at a pre-FEC BER of 2 3 10–3. (Squares: PPM; triangles: PSK; circles: QAM; diamonds: OOK.)


capacity. The lower portion of the figure belongs to the realm of sensitivity-constrained systems while the upper portion applies to capacity-constrained systems. The theoretically achievable sensitivity for four classes of modulation formats (OOK, PSK, QAM, PPM) are also shown, assuming the above mentioned 7% overhead FEC (2 3 1023 pre-FEC BER). The performance of some recent experimental results is captured by the fainter col-ored symbols. It is evident that hardware implementation dif-ficulties prevent the formats from performing at their theoretical limits, both in terms of sensitivity and spectral efficiency.

WDM system evolutionFiber-optic transport systems are the most capacity-constrained of all optical communication systems. To assess technological progress at the forefront of transmission capacity, Fig. 8 com-piles research experiments reported at the Optical Fiber Com-munication Conferences (OFC) and the European Conferences on Optical Communications (ECOC). The green data points show the experimentally achieved bit rates of electronically time-division multiplexed (ETDM) single-channel systems, which reflect the historic growth rate of the speed of semi-conductor electronics. By 2005/2006, ETDM bit rates had reached 100 Gb/s [39,40].

By the mid 1990s, the erbium-doped fiber amplifier (EDFA) had made WDM highly attractive because it could simultaneously amplify many WDM channels. This allowed the capacity of fiber-optic communication systems to scale in the wavelength domain by two orders of magnitude compared to single-channel systems, as indicated by the red data points. Up until ~2000, achieving a closer WDM channel spacing was a matter of improving the stability of lasers and of build-ing highly frequency selective optical filters; pre-2000, the increase in spectral efficiency, represented by the yellow data points in Fig. 8, was therefore due to improvements in device technologies.

When 40-Gb/s systems started to enter optical network-ing at the turn of the millennium, optical modulation for-mats [21,41] and coding5 [26] became very important, first to improve sensitivity so that the reach of 40-Gb/s systems would not fall too short of that of legacy 10-Gb/s systems. With the simultaneous development of stable 100-GHz and 50-GHz spaced optics, the modulated optical signal spectra quickly approached the bandwidth allocated to a single WDM channel, which took the increase of spectral efficiency from a device design level to a communications engineering level, and made spectrally efficient modulation important, as it had traditionally been the case in electronic and RF communication systems. Using advanced communication techniques such as coherent detection (presently still with off-line signal process-ing instead of real-time bit error counting), PDM, OFDM, and pulse shaping, spectral efficiencies have continued to increase at multi-Gb/s rates, with today’s records being at 4.2 b/s/Hz at 100 Gb/s [30, 31], 5.6 b/s/Hz at 50 Gb/s [37], and 9.3 b/s/Hz at 14 Gb/s [38]. Further scaling of spectral efficiency becomes increasingly more difficult, requiring expo nentially more

5 In submarine systems, coding was introduced well before 2000 [7,26].

constellation points per modulation symbol6. Recent studies on the fundamental capacity limits of optical transmission systems over standard single-mode fiber predict a maximum capacity of about 11 b/s/Hz over 2000 km [33,43], assuming that PDM doubles capacity compared to the reported single-polarization case.

The experimentally demonstrated record for the aggregate capacity over a single optical fiber is currently at 25.6 Tb/s at a spectral efficiency of 3.2 b/s/Hz [42]. As evident from the red data points in Fig. 8, reported capacities have noticeably started to saturate over the last few years. With continuously increasing spectral efficiencies, this can be attributed, at least in part, to the slower growth rate of single-channel ETDM bit rates, which necessitates a large increase in the number of WDM channels to achieve record capacities and makes such experiments both time consuming and expensive. For example, the above mentioned 25.6-Tb/s experiment [42] used a total of 320 ETDM channels (2 optical amplification bands, 80 wave-lengths per band, and 2 polarizations per wavelength, modu-lated at 80 Gb/s each).

All the above data indicate that WDM is still scaling in spectral efficiency and capacity at present but will likely reach fundamental as well as practical limits in the near future. There-fore, new approaches have to be explored in order to continue the scaling of capacity-constrained systems. Such approaches could include the use of lower nonlinearity or lower-loss opti-cal transmission fiber [43], transmission over extended wave-length ranges, or even the use of multi-core or multi-mode optical fiber [44].

6 Transporting k bits of information per symbol (and hence per unit bandwidth in quadrature space) requires 2k modulation symbols.

1986 1990 1994 1998 2002 200610

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Figure 8. Progress in fiber-optic transmission capacities, as report-ed at post-deadline sessions of ECOC and OFC. (Green: Single-channel ETDM rates; red: WDM aggregate capacities on a single fiber; yellow: spectral efficiency.)


ConclusionsThe success of digital information processing over the last cen-tury has triggered the demand to transport massive amounts of digital information, ranging from on-chip data buses all the way to inter-planetary distances. Optical communication systems have been replacing electronic and RF techniques starting at the most demanding capacity-constrained and sensitivity-constrained applications and are steadily progressing towards more implementation-constrained shorter-reach systems that require dense integration, low power consumption, and low cost.

Modulation and multiplexing techniques are key de-sign elements of sensitivity-constrained and capacity-constrained systems, used to harvest the bandwidth ad-vantages that optical technologies fundamentally offer. Spectrally efficient modulation will stay a key area of research for capacity-constrained systems. As WDM ca-pacities over conventional fibers are approaching their fundamental limits, breakthroughs in fiber design and in complementary multiplexing techniques are expected to further scale capacity.

AcknowledgmentThe author is grateful for discussions with many colleagues in the optical communications community, including R.-J. Essiambre, A. Gnauck, G. Raybon, C. Doerr, H. Kogelnik, A. Chraplyvy, R. Tkach, J. Foschini, G. Kramer, A. Leven, F. Fidler, T. Kawanishi, M. Nakazawa, D. Caplan, P. Pepeljugoski, Y. Vlasov, S. Jansen, S. Savory, and many others.

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Abstract: The powerful capabilities of electronic digital signal processing in the transmitter and receiver are reviewed for high bit rate fiber-optic communications.

1. IntroductionRecent developments in electronic digital signal processing technology have led to a new paradigm in fiber-optic com-munications. The realization of suitable high-speed digital-to-analog converters (DACs), analog-to-digital converters (ADCs), and digital signal processors has allowed advanced signal processing to offer substantial improvements in system performance. The signal processing can be performed in the transmitter and/or the receiver. In the transmitter, the synthe-sis of the appropriate drive signals for an optical modulator permits the generation of modulated optical signals with un-precedented control of the time-varying amplitude and phase. In the receiver, coherent detection preserves both the ampli-tude and phase of the received optical signal in the detected signal, thereby allowing for the effective mitigation of trans-mission impairments and the implementation of key receiver functions. The signal processing can be made adaptive to ac-commodate a time varying channel.

In this paper, we describe four applications of electronic signal processing: pre-compensation for chromatic dispersion and self-phase modulation, pre-compensation for optical filter-ing, the generation of advanced modulation formats, and post-compensation with coherent detection.

2. Pre-compensation for Chromatic Dispersion and Self-Phase ModulationA pre-compensating transmitter is shown in Fig. 1. A tunable laser is used as a continuous-wave (CW) source and a Mach-Zehnder modulator is used to modulate the optical field. Two types of modulators are commonly used: a dual-drive Mach-Zehnder modulator and a quadrature Mach-Zehnder modu-lator. The latter consists of two single-drive Mach-Zehnder modulators within a Mach-Zehnder interferometer. A fixed 90o phase shift in one arm of the interferometer allows for independent modulation of the in-phase and quadrature com-ponents of the optical field. The modulators are illustrated schematically in Fig. 2. For a dual-drive Mach-Zehnder modu-lator, arbitrary combinations of amplitude and phase for the optical field are difficult to obtain in practice; the accessible

portion of the complex plane is determined by the two bias and modulation voltages applied to modulator. The benefit of the increased complexity of a quadrature modulator is that this limitation is removed. The electrical drive signals in Fig. 1 for the modulator are obtained from the digital signal processor, followed by digital-to-analog conversion and amplification.

The chromatic dispersion of an optical fiber acts a linear operation on the electric field of the transmitted optical signal and its effects can be undone by linear filtering. The number of taps for a digital filter increases with the maximum amount of chromatic dispersion to be compensated. Transmitter-based electronic pre-compensation for fiber chromatic dispersion was initially proposed in [1] and [2].

The first experimental results were obtained using a proof-of-principle implementation of a 20 GSa/s 4-bit DAC [3]. A 152-tap finite-impulse response (FIR) filter was used to filter the transmit data with the complex conjugate of the fiber trans-fer function before modulating the transmitter. The calculated pre-compensated analog drive waveforms were also corrected for the frequency responses of the DACs, drive amplifiers, and

Electronic Signal Processing for Fiber-Optic CommunicationsJohn Cartledge1, David Krause2, Kim Roberts2, Charles Laperle2, Doug McGhan2, Han Sun2, Kuang-Tsan Wu2, Maurice O’Sullivan2, and Ying Jiang1

Research Highlights

1: QUEEN’S UNIVERSITY, KINGSTON, ON CANADA2: NORTEL NETWORKS, OTTAWA, ON CANADA

InputSignal

Drive Amplifier

DAC

DAC

DSPOptical

Modulator

OutputOpticalSignal

Drive Amplifier

Laser

CW OpticalInputSignal

Drive Signal

Drive Signal

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90°

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Modulated OpticalOutput Signal

Drive Signal

Drive Signal

Figure 1. Pre-compensating transmitter. DSP: digital signal processor. DAC: digital-to-analog converter.

Figure 2. Dual-drive (top) and quadrature (bottom) Mach-Zehnder optical modulators.


quadrature Mach-Zehnder modulator. The pre-compensated waveforms for a 21121 pseudo-random bit sequence (PRBS) were stored in programmable pulse pattern generators.

Fig. 3 shows the measured eye diagrams for the transmission of a 10.7 Gb/s return-to-zero differential phase-shift-keyed (RZ-DPSK) signal over single-mode fiber (G.652) [3]. Eye diagrams are shown for the back-to-back case, and after 1600, 3200, and 5120 km of fiber. The average launch power was 27 dBm. No op-tical dispersion compensation was used. For comparison, the eye diagram for 320 km without pre-compensation is also shown.

The dependence of the bit error ratio (BER) on the opti-cal signal-to-noise ratio (OSNR) of the received signal is shown in Fig. 4 for an average transmitted optical power of 27 dBm and a fiber length of 5120 km. Also included in the graph is a typical forward-error-correction (FEC) coding threshold at BER 5 3.84 3 1023; FEC decoding will correct this raw BER

to 10220. Self-phase modulation (SPM), a non-linear effect in optical fibers, prevents a BER below the FEC threshold from being obtained for 5120 km of fiber and an average transmitted optical power of 25 dBm. The linear compen-sation results can be improved further by apply-ing nonlinear pre-compensation for SPM [4]. Fig. 4 also shows results for a transmitted opti-cal power of 25 dBm with SPM compensation. The required OSNR is improved by 0.75 dB, and hence the system margin is increased by 2.75 dB, compared to linear compensation only with a transmitted optical power of 27 dBm.

Subsequently, two DACs and the digital signal processing circuits were implemented in a 2 million gate, application specific inte-grated circuit (ASIC) fabricated in 130 nm BiCMOS technology. The ASIC is capable of 6 trillion integer operations per second. The setting of the pre-compensation can be based

on estimates or knowledge of the fiber properties, or on auto-matic discovery and optimization.

3. Pre-compensation for Optical FilteringIn spectrally efficient optical networks, signals passing through multiple reconfigurable optical add-drop multiplexers can be distorted by the bandwidth narrowing that results from the cas-caded optical filtering. While pre-compensation for chromatic dispersion addresses the effects of phase distortion, here the emphasis is on the effects of amplitude distortion [5]. An opti-cal spectrum analyzer was used as a narrow bandpass filter to represent the overall response of concatenated filters. The filter had 23 dB and 220 dB bandwidths of 9.1 GHz and 20 GHz, respectively. The phase response of the filter was linear over the 230 dB bandwidth.

For 10 Gb/s non-return-to-zero on-off-keyed (NRZ-OOK) modulation, eye diagrams are shown in Fig. 5 for the transmitted and filtered optical signals, without and with pre-compensation. The transmitted signal without pre-compensation used an ideal raised-cosine pulse shape with a roll-off factor of 0.7 and a dual-drive Mach-Zehnder modulator. Qualitatively the eye diagram opens considerably when pre-compensation is used.

The corresponding dependence of the BER on the OSNR of the received signal is shown in Fig. 6 (results with solid line). The intersymbol interference due to the narrow filtering causes a 5.8 dB OSNR penalty (at BER 5 1 3 1029). With pre-com-pensation, the OSNR penalty is reduced to 1.8 dB. For a dual-drive Mach-Zehnder modulator, the extent of the improvement is limited by the requirement that the pre-compensated optical field lie within the accessible portion of the complex plane. The pre-compensation can be improved by using a quadrature mod-ulator. This is also illustrated in Fig. 6 (results with dashed line); the OSNR penalty with pre-compensation is only 0.9 dB.

4. Modulation FormatsBy using high-speed digital signal processing and DACs, modu-lation formats that require multi-level modulator drive voltages can be generated. For example, 20 Gb/s differential quadrature

0 km

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Figure 3. Eye diagrams at the receiver for 10.7 Gb/s RZ-DPSK transmission over 0, 1600, 3200, and 5120 km of single-mode fiber with pre-compensation. The eye diagram for 320 km without pre-compensation is shown for comparison. Timebase is 20 ps/div.

Figure 4. Dependence of the BER on the OSNR (0.1 nm noise band-width) with and without SPM compensation for 5120 km transmis-sion of a 10 Gb/s RZ-DPSK signal.


phase-shift keying (DQPSK) modulation can be achieved with a single dual-drive Mach-Zehnder modulator, rather than a quadrature modulator which is conventionally used for DQPSK [6]. The use of a single dual-drive Mach-Zehnder modulator to generate DQPSK was introduced theoretically in [7].

The accessible region of the complex plane is shown by the gray shaded region in Fig. 7 for a dual-drive Mach-Zehnder mod-ulator biased at extinction and peak-to-peak RF drive voltages of V

p (voltage that changes the phase by p). The constellation

points 60.5 6 j0.5 cause a 3 dB loss in the peak output power which could be avoided by using drive voltages of 1.5 V

p.

For 20 GSa/s DACs, there are two samples per symbol for the modulator drive signals. The first sample corresponds to the optical field associated with the symbol. The second sample defines the signal trajectory in accordance with the constraint indicated in Fig. 7. To select the value for the second sample, the next symbol was examined to determine the necessary tran-sition. For a repeated symbol, the second sample was a repeat of the first. For horizontal and diagonal transitions (i.e., (0,1) to (1,1) or (0,0) to (1,1)), the second sample corresponded to the origin. For vertical transitions (i.e., (1,0) to (1,1)), the sec-ond sample corresponded to 60.5 1 j0. For this demonstra-tion, the required voltages were calculated at each sample time (pre-coding, look-up table and pre-emphasis), stored in the arbitrary electrical pattern generator of the pre-compensation ASIC, and then applied to the modulator through the DACs and drive amplifiers.

Optical waveforms were generated with two different 214 deBruijn bit patterns for the in-phase and quadrature channels (denoted U and V). To visualize the optical signal, a simulation result with ideal drive voltages for 128 symbols is shown in Fig. 7. The constellation points are clearly visible. With 20 GSa/s sampling, the trajectories between constellation points tend to

Transmitted Without Pre-Compensation

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atio


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Figure 5. Eye diagrams at the transmitter and after the optical fil-ter, without and with pre-compensation. Timebase is 30 ps/div.

Figure 7. Ideal output of the dual-drive Mach-Zehnder modulator shown on the complex plane. The accessible portion of the complex plane for a dual-drive Mach-Zehnder modulator biased at extinction and peak-to-peak RF drive voltages of V

p is shown by the gray shaded region.

Figure 6. Dependence of the BER on the OSNR (0.1 nm noise bandwidth) for a 10 Gb/s NRZ-OOK signal: back-to-back without filtering, filtering without pre-compensation, and filtering with pre-compensation. Solid line: dual-drive Mach-Zehnder modulator. Dashed line: quadrature Mach-Zehnder modulator.

–1.0 –0.5 0.0 0.5 1.0–1.0

–0.5

0.0

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Imag

inar

y P

art (

V/m

)

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(1,0)(0,0)

(1,1)(0,1)

Figure 8. Left: Output optical power of the transmitter. Right: Eye diagram of the U channel after the delay interferometer. Timebase is 25 ps/div.


take arcs. The digital-to-analog conversion causes the RF drive voltages to occasionally exceed V

p, in which case the optical

field extends outside the gray shaded region.The optical power at the output of the transmitter is shown

in Fig. 8. The dips in the eye diagram indicate where transi-tions occur through the origin. Following the delayed inter-ferometer in the receiver, the eye diagram for the U channel at a BER of 131029 is also shown in Fig. 8. Since horizontal transitions pass through the origin, the upper rail is missing. The non-ideal responses of the DACs and drive amplifiers lead to a pattern dependence in the multi-level drive voltage wave-forms. This causes the broad rails in the eye diagram, which are consistent with the arc-like signal trajectories shown in Fig. 7. The dependence of the measured BER on the received optical power is shown in Fig. 9. A receiver sensitivity of 232.5 dBm at a BER of 131029 was achieved with the U and V channels differing by only 0.25 dB.

5. Coherent Detection and Post-compensationThe combination of coherent (intradyne) detection, analog-to-digital conversion, and digital signal processing provides

a powerful approach for mitigating transmission impairments and implementing required functions in a fiber-optic receiver [8]. As an example, coherent detection of dual-polarization QPSK is shown in Fig. 10. By transmitting two independent QPSK signals on orthogonal states-of-polarization, the symbol rate is 10 Gsymbol/s for a data rate of 40 Gb/s. The received signal is passed through a polarization beam splitter and de-composed into two orthogonal signals. Each orthogonal signal is applied to an optical hybrid together with a local oscilla-tor (LO) signal that is provisioned to select the WDM chan-nel. The frequency of the LO laser is controlled to be within a few hundred MHz of the carrier frequency for the received signal. The four resulting polarization and phase orthogonal signals are detected by individual photodiodes, amplified, filtered and then digitized using four 20 GSa/s ADCs with 6-bit resolution. The ADCs and the overall receiver circuits have a net 3 dB bandwidth of 6 GHz. Clock recovery, carrier recovery, polarization tracking, polarization mode dispersion (PMD) tracking, and dispersion compensation are performed digitally, requiring 12 trillion integer operations per second. The post-compensation adapts to time variations in the chan-nel (e.g., temperature-induced changes in the chromatic dis-persion). The four ADCs, digital signal processing circuits, and a supervisory processor have been implemented in a cus-tom mixed-signal 20 million gate ASIC using 90 nm CMOS technology (Fig. 11).

To test the tolerance to dispersion and PMD, a 46.008 Gb/s (11.502 Gbaud) signal was transmitted through a link consist-ing of 900 km of single mode fiber (G.652) and PMD emula-tion. The link did not have any optical dispersion compensation. The bit rate includes 7% overhead for FEC coding and a 23121 pseudo-random bit sequence was used in the transmitter. White amplified spontaneous emission noise was added before the receiver to vary the OSNR. The net dispersion of about 15000 ps/nm (900 km 3 16.7 ps/km/nm) was entirely compensated in the re-ceiver ASIC. In order to assess the purely linear performance of the coherent receiver, the launch power was kept below 26 dBm after each amplifier for a single optical channel.

Fig. 12 shows the measured BER of this link, with add-ed first-order PMD (peak differential group delay) of 0 and 50 ps. The fiber and amplifier PMD is negligible. The FEC threshold at BER 5 3.84 3 1023 is also shown. The re-quired OSNR is 10.8 dB (0.1 nm noise bandwidth) at the

FEC threshold. For comparison, results are also shown for the theoretical and measured back-to-back performance. The receiver is robust to 50 ps of rapidly varying first- order PMD and 15,000 ps/nm of dispersion as the three measured curves are the same, within experimental error. Recently, a rig-orous assessment of the transmission perfor-mance of a 46 Gb/s dual-polarization QPSK transceiver has been performed [9].

6. ConclusionAdvanced electronic signal processing for fiber-optic transmitters and receivers has enabled dramatic improvements in

Figure 9. Dependence of the BER on the received optical power for the U and V channels.

Figure 10. Block diagram of a dual-polarization QPSK receiver. PBS: polarization beam splitter. PMS: polarization maintaining splitter. PD: photodiode. ADC: analog-to-digital converter. DSP: digital signal processor.

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transmission performance and substantially enriched the field of fiber- optic communications. To illustrate these attributes, we have briefly described four applications: pre-compensation for chromatic dispersion and self-phase modulation, pre- compensation for optical filtering, the generation of advanced modulation formats, and post-compensation with coherent detection.

ReferencesR. I. Killey, P. M. Watts, V. Mikhailov, M. Glick, and 1. P. Bayvel, “Electronic dispersion compensation by signal predistortion using digital signal processing and a dual-drive Mach-Zehnder modulator,” IEEE Photon. Technol. Lett., vol. 17, no. 3, pp. 714–716, 2005.J. McNicol, M. O’Sullivan, K. Roberts, A. Comeau, 2. D. McGhan, and L. Strawczynski, “Electrical domain compensation of optical dispersion,” in Proc. Conf. Optical Fiber Commun., Anaheim, CA, 2005, Paper OThJ3.D. McGhan, C. Laperle, A. Savchenko, C. Li, G. Mak, and 3. M. O’Sullivan, “5120-km RZ-DPSK transmission over G.652 fiber at 10 Gb/s without optical dispersion com-pensation,” IEEE Photon. Technol. Lett., vol. 18, no. 2, pp. 400–402, 2006.

K. Roberts, C. Li, L. Strawczynski, M. O’Sullivan, and I. 4. Hardcastle, “Electronic precompensation of optical non-linearity,” IEEE Photon. Technol. Lett., vol. 18, no. 2, pp. 403–405, 2006.D. J. Krause, Y. Jiang, J. C. Cartledge, and K. Roberts, 5. “Pre-compensation for narrow optical filtering of 10 Gb/s intensity modulated signals,” IEEE Photon. Technol. Lett., vol. 20, no. 9, pp. 706–708, 2008.D. J. Krause, J. C. Cartledge, and K. Roberts, “Demonstra-6. tion of 20-Gb/s DQPSK with a single dual-drive Mach-Zehnder modulator,” IEEE Photon. Technol. Lett., vol. 20, no. 16, pp. 1363–1365, 2008.K.-P. Ho and H.-W. Cuei, “Generation of arbitrary quadra-7. ture signals using one dual-drive modulator,” J. Lightwave Technol., vol. 23, no. 2, pp. 764–770, 2005.H. Sun, K.-T. Wu, and K. Roberts, “Real-time measure-8. ments of a 40 Gb/s coherent system,” Optics Express, vol. 16, no. 2, pp. 873–879, 2008.L. E. Nelson, S. L. Woodward, S. Foo, X. Zhou, M. D. 9. Feuer, D. Hanson, D. McGhan, H. Sun, M. Moyer, M. O’Sullivan, and P. D. Magill, “Performance of a 46-Gbps dual-polarization QPSK transceiver with real-time co-herent equalization over high PMD fiber,” J. Lightwave Technol., submitted for publication.

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Figure 12. Measured BER for single channel transmission in a 900 km link (chromatic dispersion (CD) of 15,000 ps/nm), with and without PMD (differential group delay (DGD) of 50 ps). For comparison, theoretical and measured results for the back-to-back performance are also shown.

Figure 11. CMOS receiver ASIC with four ADCs and digital signal processor.


Radio over Fiber Distributed Antenna NetworksMichael J. Crisp, Student Member, IEEE, Sithamparanathan Sabesan, Student Member, IEEE, Richard V. Penty, Senior Member, IEEE and Ian H. White, Fellow, IEEE

Research Highlights

ELECTRICAL ENGINEERING DIVISION, UNIVERSITY OF CAMBRIDGE, CB3 0FA, CAMBRIDGE, U.K

(E-MAIL: [email protected])

IntroductionThe rapid evolution and convergence of wireless technologies and services, coupled with the emerging trend of frequency mi-gration of existing services, is leading to in-building wireless service provision becoming a complex battleground for both businesses and operators alike. Such companies now need the agility and infrastructure to quickly and cost-effectively deploy new wireless services and upgrade applications on demand in order to retain consumer loyalty, generate new revenues and enable greater productivity from employees.

At the same time, to meet the increased demand for band-width, the carrier frequency of wireless services has been forced higher, and spectral efficiency has been increased, resulting in reduced system tolerance to the poor radio environment within buildings. In order to overcome the problem of poor propagation, antennas must be distributed around buildings, reducing the effect of free-space losses and multipath effects. Traditionally this is achieved either by distributing base sta-tions around the building (as is common in wireless local area network (LAN) installations) or by centrally locating all the radio hardware at a single location and using some form of dis-tributed antenna system (DAS). In the past, such systems have been implemented using coaxial cables and leaky feeder anten-nas, even though the limited bandwidth and high attenuation of coax in the gigahertz frequency range may require a separate network to be used for each wireless service. A traditional in-building wireless installation is shown in Figure 1. Here a leaky feeder DAS is providing 3G coverage and a distributed wire-less LAN service. In practice, large buildings would have many more networks. As wireless services migrate to higher carrier frequencies this approach becomes less commercially and tech-nically attractive as the cost-performance tradeoff worsens.

The lower losses and wide bandwidth offered by optical fi-ber enable radio over fiber based distributed antenna systems to carry all required services on a single network as shown in Figure 2. Research at Cambridge has sought to develop low-cost DAS units that can operate over any of the common trans-mission media − single mode optical fiber, multimode optical fiber or coax cable − and allow multiple services to be trans-mitted simultaneously. In order for low-cost operation to be achieved, work has focused on the use of uncooled laser diodes at the transmitter. Recently, the results of this work, much

of it carried out in collaboration with Professor Alwyn Seeds of University College London, have been commercialized by Zinwave Ltd [1].

The optical DAS typically consists of a hub unit in the equipment room, which in the downlink combines the radio frequency (RF) signals from the base stations and performs electrical-to-optical conversion, normally by applying the RF signal as a modulation current directly to the laser bias. The optical signal is then carried over optical fiber to the antenna unit where optical-to-electrical conversion is performed by a photodiode before the RF signal is amplified and transmitted from an antenna. In the uplink (mobile station to base station), the process is identical but reversed.

A key aspect to the links that are now being commercial-ized by Zinwave is their broadband nature over the 300 MHz to 2.7 GHz frequency range. Previously, performance over the 1 GHz to 20 GHz range was been demonstrated by an un-cooled laser operating over both single and multimode opti-cal fiber [2]. Since the optical link is essentially transparent to the RF signal, and is agnostic to the modulation formats and

3G LAN

Figure 1. A traditional wireless installation with distributed WLAN hardware and a separate 3G leaky feeder installation.


protocols in use, an upgrade to accommodate future services only requires modification of the base station in the equipment room. By comparison, a traditional installation would require changes to the hardware throughout the building, either by changing a distributed hardware installation or by installing a new coax distribution system. Additional advantages of the optical DAS approach include enhanced security by careful control of the radio footprint and reduced power requirements at each antenna.

As a result, the Zinwave DAS allows businesses and facili-ties to deploy a single, centrally managed platform to sup-port multi-service/multi-operator wireless coverage without requiring either parallel service specific units or cabling overlays. Any number or combination of services are sup-ported – including 2G/3G to LTE, WiFi, WiMAX, TETRA, private mobile radio, RFID and DVB-H – enabling simul-taneous mobility for employees, consumers and emergency services. It also uniquely supports Time Division Duplex (TDD) services. Importantly, the system supports new and frequency migrating services without the need for disruptive and costly upgrades, additional hardware, or cable overlays. Indeed the systems incorporate a built-in Element Manage-ment System (EMS), for centralised monitoring and configu-ration. A web-based interface allows the RF management features to be accessed directly and integrated into existing management systems.

Progression from DAS to DANWhile DAS have the potential for reducing the maintenance burden by allowing centralized location of hardware and us-ing fiber to remote the antennas, distributed antenna networks (DAN) that allow multicasting and eventually switching of the same RF signal over several antennas will bring a range of other improvements. Recent research at Cambridge therefore has focused on the opportunities arising from DAN.

Within a DAN, multicasting may be carried out in the electrical domain through careful circuit design. However, op-tical splitting allows the full bandwidth of optical fiber to be exploited. As a 3dB splitting loss in the optical domain results in a 6dB loss in the RF signal, optical amplification must be employed for large splits to overcome the losses. Cambridge has demonstrated such a multicast system with up to 256 splits using semiconductor optical amplifiers (SOAs) as the gain block [3]. More recently silicon avalanche photodiodes (APDs) have been used to increase the receiver sensitivity in short wavelength links [4].

The use of SOA switch matrices in RoF links can also enable radio service switching functionality, which brings the poten-tial for dynamic management of radio resources in response to demand. For example, in an airport departure gate, there may be a large demand for bandwidth just prior to boarding, but the gate may then remain unused for a number of hours. With a switched DAN, the shapes and locations of cells could be managed to meet this dynamic demand with a far lower overhead of excess base-station capacity than is currently used using conventional static approaches. We have carried out demonstrations of 32x32 RoF switches similar to those un-der development for data communications applications. Using

IEEE 802.11g signals as a test case, an EVM of less that 4% has been achieved across the switch using three cascaded SOAs [5]. This performance is well within the 5.6% limit for 54 Mbps operation of IEEE 802.11g.

Propagation Effects using an Optical DANThe low loss offered by optical fiber allows a fiber-fed DAN to operate in ways not previously possible with co-axial ca-bles. For instance, the lower attenuation may give rise to long propagation delays along the fiber. Coupled with an ability to transmit the signal from multiple antennas, this gives rise to potential multi-path effects with path differences (mainly in the fiber) much greater than those generally seen in conven-tional wireless systems.

Detailed experiments have however shown, that provided these differences in delay are kept within certain (service de-pendent) limits, that a DAN can provide greatly improved wireless coverage compared to single antenna systems. Figure 3 shows a comparison of the downlink IEEE 802.11g throughput of a single antenna system and a 3-antenna DAS using the same total output power. Detailed analysis shows that the single antenna would in this case require 15 dB more power to achieve the same quality of coverage as the 3-antenna system [6]. The increase in power requirement if a DAN is not used also increases the requirements for antenna isolation between the up and downlinks, and dynamic range requirements. Similar improvements have been demonstrat-ed in the uplink and with other services. Figures 3(b) and 3(c) show a comparison of the DAN with equal fiber lenghts and with one AU fed by a fiber 30 m longer. It can be seen that this additional delay and multipath does not degrade the performance.

Figure 2. Example building with a multi-service optical DAS

3GHUB WLAN


Converged Sensing and Communications Networks Using an Optical DASRadio over fiber research to date has focused on providing wireless communications services, reaching commercial de-ployment in many cases. However, future requirements for

intelligent infrastructure are likely to in-clude sensor networks in addition to com-munications services. In a manner simi-lar to that in communications services, a barrier to the widespread introduction of many sensor networks is the cost of in-stallation and deployment, so an overlay of the sensor network on the communi-cations infrastructure makes economic sense. While the various communications standards in use have broadly similar re-quirements from the optical link in terms of output power, bandwidth, noise, and linearity, sensor networks bring a new set of challenges.

One sensing system of particular in-terest is passive UHF RFID. By transmit-ting a high power carrier in the downlink, RFID tags are able to operate without an internal power supply greatly reducing cost. However, the required downlink power is typically 20–30 dB greater than that for short-range wireless communica-tions services. As a result of the higher output power, if RFID and communica-tions services are carried on the same opti-cal network, the high power of the RFID service induces nonlinear distortion in the laser diode. For a typical broadband DAS with a bandwidth of 300 MHz to 2.7 GHz, the generated second harmonic of UHF RFID in the 900 MHz band will occur at 1.8 GHz, within the bandwidth of the DAS. Regulations strictly limit the allowed levels of such spurious emis-sions to prevent unwanted interference in other wireless systems. Conventionally, a filter would be used before the antenna to reduce out of band spurious emissions to acceptable levels. However, to maintain the transparent broadband nature of the DAS and allow future upgrades it is de-sirable to not have to add any additional hardware at the antenna unit. In order to reduce the level of the second harmonic in this case, a simple electronic cancella-tion scheme has been developed. Using this scheme a RoF link has been dem-onstrated to support IEEE 802.11g and RFID simultaneously [7].

Besides allowing easier deploy-ment of RFID along side communica-tions networks on a common infrastruc-

ture, optical DAS are able to bring coverage improvements to passive UHF RFID similar to those seen in communica-tions networks. Figure 4 shows the returned power from a passive UHF RFID tag in a single and 3-antenna DAS. A level of 285 dBm represents nulls where no returned signal

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from the tag can be detected. Through the use of the DAS, the number of nulls has been reduced from 28% to 0%, and a 10 dB increase in the returned power has been achieved over an 8 m range. Similar improvements have been demonstrated over a range up to 18 m using a commercial RFID reader and an optical DAS [8].

Future potentialOptical DAS are reaching a level of maturity where commer-cial installations are becoming widespread. However, with the constantly increasing bandwidth demands and evolving sens-ing and communications standards, a large body of research remains to be carried out.

Topics of interest include:Lower cost optical links – for example, recent research on • polymer optical fiber has demonstrated very promising RoF performance.Intelligent DANs - to date DANs have been largely static • although research has shown that RoF optical switching is possible. Combining a switched DAN with sensing will produce a new intelligent infrastructure, with the abil-ity to self-manage, further improving the quality of the services offered and the possibility to become resilient to failure.MIMO systems – A few demonstrations of MIMO on RoF • have been carried out, but DAN systems have only used multiple antennas to achieve diversity. Spatial multiplex-ing within a DAN has the potential for greatly increased bandwidths.

Referenceshttp://www.zinwave.co1. mP. Hartmann, X. Qian, A. Wonfor, R. V. Penty, and I. H. 2. White, “1-20GHz directly modulated radio over MMF

link,” presented at the IEEE Topical Conf. on Microwave Photonics, Seoul, 2005.X. Qian et al., “Application of semiconductor optical am-3. plifiers in scalable switched radio-over-fiber networks,” presented at the IEEE Topical Conf. on Microwave Photo-nics, Seoul, 2005.F. Yang, M. J. Crisp, R. V. Penty, and I. H. White, “Silicon av-4. alanche photodiodes for low cost, high loss short wavelength radio over fiber links,” CLEO, submitted for publication.M.J. Crisp, E.T. Aw, A. Wonfor, R.V. Penty, and I. H. 5. White, “Demonstration of an SOA efficient 32332 opti-cal switch for radio over fiber distribution,” OFC, vol. 7, 2008.<AU: please provide the issue number and the complete page range.>M.J. Crisp, S. Li, A. Watts, R.V. Penty, and I. H. White, 6. “Uplink and downlink coverage improvements of 802.11g signals using a distributed antenna network,” J. Lightwave Technol., vol. 25, pp. 3388–3395, 2007.<AU: Please provide the issue number.> M. J. Crisp, R. V. Penty, and I. H. White, “Dual function 7. sensing and multiservice communications radio over fiber network using second harmonic suppression,” OFC, to be published.S. Sabesan, M. J. Crisp, R. V. Penty, and I. H. White, 8. “Demonstration of improved passive UHF RFID coverage using optically-fed distributed multi-antenna system,” to be presented at RFID Conf.

Glossary of Terms2G/3G – Second/Third Generation (cellular phones)DAS – Distributed Antenna SystemDAN – Distributed Antenna Network DVB-H – Digital Video Broadcast - Handheld (European stan-dard for digital broadcast television for mobile devices, and is a variant of the Terrestrial standard, “DVB-T”, that was defined for non-mobile devices. LAN – Local Area NetworkLTE – Long-Term Evolution (The standard is 3GPP Release 8, for many a “4G” technology) RFID – Radio Frequency Identification (RFID) systems typi-cally consist of a tag that contains information identifying an item. Ultra-high frequency (UHF) RFID tags can operate from 300 MHz to 3 GHz, but typically between 866 MHz to 960 MHz. They can send information faster and further than high and low frequency tags but require greater power.TDD – Time Division Duplex TETRA – Terrestrial Trunked Radio, the ETSI standard for digital trunked radio communications Wifi – Wireless Fidelity (This usually refers to a wireless networking system that uses any of the 802.11 (including 802.11a/b/g) wireless networking protocols. The Wi-Fi stan-dard is set by the Wi-Fi Alliance.)WiMAX – Worldwide Interoperability for Microwave Access (Technology to deliver wireless broadand access over distances of up to 6 miles, an alternative to broadband access via a fixed line local loop. WiMAX is based on IEEE 802.16)

Figure 4. Comparison of the returned power in a single antenna RFID system and an RFID system using a 3-antenna DAS. −85 dBm has been used to represent nulls where no returned power could be detected.

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Biographies Michael J. Crisp (S’07) received the B.A. degree from the Uni-versity of Cambridge, U.K., the M.Eng. degree from the Uni-versity of Cambridge in 2005, and is currently working toward the Ph.D. degree in optical communications at the University of Cambridge, conducting research on RoF.

Sithamparanathan Sabesan (S’08) was born in Jaffna, Sri Lanka, in 1984. He received the B.Eng. (Hons) degree from the University of Sheffield, Sheffield, U.K., in 2007, and the MPhil degree in Engineering from the University of Cam-bridge, Cambridge, U.K., in 2008. He is currently working toward the Ph.D. degree in optical and wireless communica-tions, conducting research on passive UHF RFID and RoF at the same University. He was with ARM, Cambridge, U.K. as a student IP Electronic Engineer in 2007. Mr. Sabesan was awarded a Sir William Siemens Medal in 2006.

Richard V. Penty (M’00-SM’08) received the Ph.D. degree in engineering for his research on optical fiber devices for signal processing applications from the University of Cambridge, U.K., in 1989. He was a Science and Engineering Research Council (SERC) Information Technology Fellow, again at the University of Cambridge, working on all optical nonlinearities in waveguide devices. He is currently a Professor of Photonics at the Univer-

sity of Cambridge, having previously held academic posts at the Universities of Bath and Bristol. His research interests include high speed optical communications systems, wavelength conver-sion and wavelength division multiplexing (WDM) networks, optical amplifiers, optical nonlinearities for switching applica-tions, and high power semiconductor lasers. He has been the author of more than 400 refereed journal and conference papers. Prof. Penty is the Editor-in-Chief of IET Optoelectronics.

Ian H. White (S’82–M’83–SM’00–F’04) received the B.A. and Ph.D. degrees from the University of Cambridge, U.K., in 1980 and 1984, respectively. He was appointed as Research Fellow and Assistant Lecturer at the University of Cambridge before he became Professor of Physics at the University of Bath, U.K., in 1990. In 1996, he moved to the University of Bris-tol, U.K., where he was Professor of Optical Communications, Head of the Department of Electrical and Electronic Engineer-ing in 1998, and Deputy Director of the Centre for Communi-cations Research. He returned to the University of Cambridge in October 2001 as van Eck Professor of Engineering. He is the Head of the School of Technology and of Photonics Research at the University of Cambridge. He has published in excess of 400 publications and 20 patents. Prof. White is currently an Editor-in-chief of Electronics Letters and a member of the Board of Governors of the IEEE LEOS Society.


Enabling Microwave Photonic Technologies for Antenna RemotingDr Dalma Novak

The low-loss, electromagnetic interference free, and wide bandwidth microwave signal transport over lightweight and non-conducting photonic links offers the potential for provid-ing new capabilities, significant performance improvements, and design flexibility to a diverse range of microwave systems [1,2]. In this article we describe some enabling microwave photonic technologies for fiber-optic antenna remoting in RF sensor systems and wireless communication networks.

Adaptive Feedforward Linearization for High Dynamic Range RF Photonic LinksA major hurdle to fully realizing the benefits of photonic sig-nal remoting in microwave systems is the high dynamic range requirement of many applications, limited by the inherent nonlinearity of the electrical-to-optical (E/O) conversion pro-cess. Several linearization schemes suitable for correcting mi-crowave photonic link nonlinearities have been demonstrated, most derived from common RF amplifier design techniques such as predistortion [3,4] and feedforward [5,6] architectures. Novel electro-optical modulator designs [7] have also been pro-posed and demonstrated. The majority of these implementations, however, have been characterized by limited operational and/or instantaneous bandwidths, as well as the achievable Spurious Free Dynamic Range (SFDR).

Recently, in collaboration with research-ers at Johns Hopkins University Applied Physics Laboratory, we developed a linear-ized high SFDR RF photonic link with multi-octave operational bandwidth and an instantaneous bandwidth approaching 1 GHz [8]. Our approach for correcting the performance-limiting E/O nonlinear dis-tortion was based on the use of feedforward (FF) linearization. Figure 1 shows the high level architecture of the linearized circuit which is based on an intensity modula-tion direct detection link and also incor-porates adaptive functionality. As shown in the diagram, an electro-optic modulator (EOM) encodes the input RF signal(s) onto an optical carrier. Distortion due to this nonlinear transfer function is dominated

by third-order intermodulation distortion products (IMD3) which are important to suppress since they typically lie within the frequency band of interest. The adaptive FF linearization architecture incorporates three main parts: a signal cancellation circuit (SCC), an error cancellation circuit (ECC), and a control circuit (CC). Control loops are also utilized to provide real-time adaptive capability whereby the RF photonic link can maintain system performance during changing operating conditions. As their names imply, the SCC and ECC cancel the signal and er-ror respectively, forming the foundation of a conventional FF linearization system.

As highlighted in Figure 1, the input RF signal to the FF linearized RF photonic circuit is split into three paths. In the SCC, the amplitude and phase of one of the copies of the input signal (represented by the ‘DA, Dw’ block) is adjusted for maxi-mum signal cancellation when it is combined with a portion of the main optical path after optical-to-electrical (O/E) conversion in a high-speed photodetector (PD). The main optical signal and the input RF replica are arranged to have equal amplitudes and

Research Highlights

Figure 1. Top: Block diagram of the wideband adaptive FF linearization transmission circuit architecture; Bottom: Photograph of the RF photonic transceiver module.

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opposite phase when combined; the signal component is then cancelled leaving only the error. The error signal is then prepared by amplitude and phase adjustment and encoded with a second EOM in the ECC before being optically coupled back into the main transmission path. Proper error cancellation occurs when these two signals are equal in amplitude and opposite in phase and ideally, an undistorted copy of the input RF signal through the transmission medium at the final O/E conversion will result. The CC in the adaptive FF linearized RF photonic link is effec-tively a signal cancellation loop that monitors the performance of the circuit. It operates in a similar way to the SCC; combining the amplitude and phase adjusted section of the undistorted in-put RF signal and a fraction of the transmitter output to isolate the remaining distortion component of the output signal.

The operating bandwidth of the circuit shown in Figure 1 is dependent only on the frequency response of the compo-nents and the path length difference of the delay lines at the signal and error combination points. Commercial-off-the-shelf devices were used to realize a multi-octave operational band-width. Each control loop in the adaptive FF circuit includes amplitude and phase tuning hardware as well as a wideband RF detector to provide feedback on the loop performance. The detectors provide a voltage proportional to the RF signal

strength at their specific locations. A control circuit interfaces between the various components in the control loops and also executes the control algorithms. Further information regard-ing the adaptive algorithms can be found in [7].

The linearity performance of the adaptive FF linearized RF photonic circuit was measured over the RF component limited operational bandwidth of 1–20 GHz using the test configura-tion shown in Figure 2 with an input test signal comprising a two-tone RF signal centered at 15 GHz. Fundamental and IMD3 levels were measured using a high frequency RF spec-trum analyzer. Figure 2 shows an example of the measured IMD3 suppression performance and presents the measured RF spectra of the detected optical output signal with and without adaptive FF linearization implemented. IMD3 suppression of third order intermodulation distortion products by 20–25 dB in a 30 MHz instantaneous bandwidth (IBW) was achieved with the adaptive FF linearized circuit. The SFDR of the multi-octave adaptive FF linearized RF photonic link was determined from the IMD3 suppression measurements and the measured noise floor of the system. Table I summarizes the measured linearity performance of the link at instantaneous bandwidths of 30 MHz and 300 MHz, highlighting the SFDR. Table II presents the measured SFDR at a center frequency of 10 GHz

–100

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.975

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(a) (b)

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To FiberLink

From FiberLink

RF SpectrumAnalyzer

Σ

Figure 2. Top: Test configuration used to measure the linearity performance of the wideband adaptive FF linearized RF photonic trans-ceiver; Below: Measured IMD3 suppression of the wideband RF photonic link at 15 GHz with a 10 MHz two-tone spacing: (a) without and (b) with adaptive FF linearization.


for increasing instantaneous bandwidths. SFDR values in excess of 111 dB-Hz2/3 were achieved for instantaneous bandwidths approaching 1 GHz.

Antenna Technologies for Fiber Optic Antenna Remoting LinksHigh performance RF photonic links are not the only require-ment for fiber optic antenna remoting applications. Efficient, low loss interfaces between the guided optical medium and the free-space microwave link are also necessary for maximizing overall system performance. To address this challenge, Pharad is developing unique antenna technologies that are compat-ible with efficient integration with common photonic materi-als such as lithium niobate and indium phosphide. In order to support wideband fiber optic antenna remoting links, we are also focusing on broadband antenna structures that can be directly integrated with optical transmitters and receivers. The challenge lies in not compromising either the overall antenna bandwidth or the efficiency of the RF photonic link, since con-ventional antennas developed on high dielectric constant mate-rials typically feature poor efficiency and limited bandwidth.

Low profile patch-based antennas can provide efficient, broadband radiator solutions that can be either readily devel-oped on photonic materials, or electromagnetically coupled to them. Figure 3 shows a variation of this type of radiator struc-ture, known as a hi-lo stacked patch [8, 9], which can be in-tegrated on photonic materials and still provide an inherently broadband, efficient solution. The patch antenna is created on

the photonic device material where the RF electrode structure is developed (a microstrip transmission line is shown in Figure 3). Another patch antenna created on a separate combination of di-electric layers is then electromagnetically coupled to the driven antenna. This second radiator enhances the overall efficiency and bandwidth of the antenna.

Figure 4 shows the return loss performance of a hi-lo stacked patch antenna that was designed for operation at approximately 5 GHz and for integration with InP. As can be seen from the re-sponse, a −10 dB return loss bandwidth of approximately 20% was achieved using the radiator structure shown in Figure 3. Furthermore, the overall efficiency of the antenna was greater than 92%, even though the driven patch was developed on a high dielectric constant material (e

r . 11).

ConclusionThe growing spectral demands of existing microwave systems, as well as new technology opportunities such as high data rate wireless communications, make photonic signal remoting ca-pabilities likely to see increased insertion opportunities in the near as well as far future. High performance RF photonic link and antenna technologies are key to realizing these systems.

AcknowledgementThe development of the wideband adaptive RF photonic transceiver was supported in part by the Naval Air Systems

MicrostripElectrode

ParasiticPatch

DrivenPatch

z

yx

Figure 3. Schematic of a hi-lo stacked patch antenna that can be integrated with photonic materials.

0

–5

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urn

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)

–253 3.5 4.5

Frequency (GHz)5.5 64 5

Figure 4. Return loss response of a hi-lo stacked patch antenna designed for operation at 5 GHz and to be integrated with InP.

Instantaneous Bandwidth (MHz) SFDR (dB-Hz2/3)

3 113.91

30 114.03

150 113.81

300 111.16

600 113.10

900 111.40

Table II. Measured SFDR of the multi-octave adaptive FF lin-earized RF photonic link at 10 GHz for different instantaneous bandwidths.

Band

Center Frequency

(GHz)

SFDR (dB-Hz2/3)

30 MHz IBW300 MHz

IBW

S-band 3 112.97 111.86

C-band 6.5 111.76 111.90

X-band 10 114.03 111.16

Ku-band 15 115.24 111.07

Table I. Measured SFDR of the multi-octave adaptive FF linear-ized RF photonic link at 30 MHz and 300 MHz instantaneous bandwidth.


Command, Patuxent River, MD. Key collaborators at our research partner, Johns Hopkins University Applied Physics Laboratory are Dr. Thomas Clark and Mr. Sean O’Connor.

About the AuthorDalma Novak is a Vice-President at Pharad, LLC located in Glen Burnie, Maryland. She has over 16 years of experience in the microwave photonics and optical communications fields, with more than 250 publications in these areas. From 1992–2004 Dr. Novak was a faculty member in the Department of Electrical and Electronic Engineering at The University of Mel-bourne, Australia, where she is now a Professorial Fellow. From June 2001–December 2003 she was a Technical Section Lead at Dorsál Networks, Inc. and later at Corvis Corporation where she led cross-disciplinary R&D teams developing networking hard-ware for telecommunications applications. In 2007 Dr. Novak was elected to the grade of IEEE Fellow for contributions to enabling technologies for the implementation of fiber radio sys-tems. She received the PhD degree in Electrical Engineering from the University of Queensland, Australia, in 1992.

ReferencesS. A. Pappert, R. Esman, and B. Krantz, “Photonics for RF 1. systems,” in Proc. IEEE Avionics, Photonics, and Fiber-Optics Technology Conf., San Diego, CA, Oct. 2008, pp. 5–6.J. Capmany and D. Novak, “Microwave photonics com-2. bines two worlds,” (Invited Paper), Nature Photon., vol. 1, no. 6, pp. 319–331, June 2007.

C. H. Cox III, E. I. Ackerman, G. E. Betts, and J. L. 3. Prince, “Limits on the performance of RF-over-fiber links and their impact on device design,” IEEE Trans. Microwave Theory Tech., vol. 54, no. 2, pp. 906–920, 2006.R. Sadhwani and B. Jalali, “Adaptive CMOS predistortion lin-4. earizer for fiber-optic links,” J. Lightwave Technol., vol. 21, pp. 3180–3193, 2003.<AU: Please provide the issue number.>L. Roselli, V. Borgioni, F. Zepparelli, F. Ambrosi, 5. M. Comez, P. Faccin, and A. Casini, “Analog laser pre-distortion for multiservice radio-over-fiber systems,” J. Lightwave Technol., vol. 21, pp. 1211–1223, 2003.<AU: Please provide the issue number.>L. S. Fock and R. S. Tucker, “Simultaneous reduction of in-6. tensity noise and distortion in semiconductor lasers by feed-forward compensation,” Electron. Lett., vol. 27, pp. 1297–1299, 1991.<AU: Please provide the issue number.>S. H. Park and Y. W. Choi, “Significant suppression of the 7. third intermodulation distortion in transmission system with optical feedforward linearized modulator,” IEEE Pho-ton. Technol. Lett., vol. 17, no. 6, pp. 1280–1282, 2005.R. B. Waterhouse, “Stacked patches using high and low 8. dielectric constant material combination,” IEEE Trans. Antennas Propagat., vol. 47, pp. 1767–1771, 1999.<AU: Please provide the month.>W. S. T. Rowe and R. B. Waterhouse, “Efficient wide-9. band printed antennas on Lithium Niobate for OEICs,” IEEE Trans. Antennas Propagat., vol. 51, pp. 1413–1415, 2003.<AU: Please provide the month.>


President’s Column(continued from page 3)

be more news about this exciting venture shortly, but there will be an opportunity for all LEOS members to contribute to the success of the journal simply by submitting their best papers!

I also congratulate the newly elected members of the Board of Governors:

Shun Lien Chuang (University of Illinois)• Jeffrey A. Kash (IBM Research, NY)• Michal Lipson (Cornell University, NY)• Ian White, (University of Cambridge, United Kingdom) • and thank the outgoing elected members, Markus Amann, Kent Choquette, Hideo Kuwahara and Carmen Menoni.

Changes in the societyThe Society will be launching several new initiatives this year, and I have selected a few highlights.

In addition to the IEEE Photonics Journal, the IEEE/OSA Journal of Optical Communications and Networking ( JOCN ) will start in 2009. The formal launch will be in April, with a ma-jor publicity drive at OFC. The other co-sponsors are the IEEE Communications Society and OSA. The JOCN will offer compre-hensive coverage of advances in theoretical and practical aspects of state-of-the-art optical communication systems and networks. It is complementary to the Journal of Lightwave Technology, which is oriented towards device and hardware implementation. Please consider publishing relevant papers in this Journal.

The Society will be co-sponsoring the IEEE Photovol-taic Specialists Conference for the first time. This reflects the increasing importance of photonics in meeting the needs for renewable energy.

There is also a major change in the Technical Commit-tee structure, with the 18 old committees being reduced to 12 from 1st January. This change is intended to allow for the creation of new TCs in areas of increasing importance.

A new personal emphasis The observant amongst you will have noticed a change in my affiliation in the list of Society officers. Although I remain affiliated to both the University of Glasgow and Intense Ltd, I will now be spending the bulk of my time in the University – another signifi-cant change from the New Year.

Building the LEOS community Finally, some news about membership. As we enter 2009, Society membership has risen above 7000, the highest December membership total since 2005. This excellent news reflects both the relevance and importance of the field of photonics and the high quality products LEOS offers to the field. I would like to welcome the new members and to thank everyone who has been involved in their recruitment. This is a tremendous achievement in the current economic climate, and I am sure we can continue to grow as we expand into new technical areas and develop our conferences and journals.


2009 IEEE/LEOS FellowsCongratulations!Please join us in congratulating the 16 LEOS members who became IEEE Fellows this year. It’s a significant honor that is based on major technical contributions, leadership, and service to the Institute and the profession.

The deadline for 2010 Fellow nominations is March 1. For more information, and to learn how to submit a nomination, check out the Fellows page on the IEEE portal at: http://www.ieee.org/web/membership/fellows/index.html

Piet DemeesterGhent University, IBBT - Gent, BelgiumFor contributions to optical communication networks and technologies

Ching-Ting LeeNational Cheng Kung University, College of EE & CS - Tainan, TaiwanFor contributions to galium nitride-based optoelectronic and electronic devices

Keren BergmanColumbia University, Dept. of Elec-trical Engineering - New York, NY, U.S.A.For contributions to development of optical interconnection and transport networks

David BradyFitzpatrick Institute for Photonics & Dept. of Electrical Engineering Pratt School of Engineering, Duke Univer-sity (DISP) - Durham, NC, U.S.A.For contributions to computational optical imaging and spectroscopy

Gary CarterUniversity of Maryland Baltimore County, Computer Science & EE Dept. - Baltimore, MD, U.S.A.For contributions to understanding non-linear and polarization effects in optical fiber communications systems

John CartledgeQueen’s University, Dept of Electrical and CE Walter Light Hall - Kingston, ON, CanadaFor contributions to modulation dynamics of optical devices

Weng ChowSandia National Laboratories - Albuquerque, NM, U.S.A.For contributions to semiconductor-laser theory

Andrew ChraplyvyBell Laboratories, Alcatel-Lucent - Holmdel, NJ, U.S.A.For contributions to high-capacity optical communications systems, dispersion man-agement and non-zero dispersion fiber

Martin DawsonUniversity of Strathclyde, Institute of Photonics - Glasgow, Scotland, UKFor contributions to compound semiconduc-tor optoelectronics

Alan GnauckBell Laboratories, Alcatel-Lucent - Holmdel, NJ, U.S.A.For contributions to high-capacity optical communications systems

Franz KaertnerMassachusetts Institute of Technology - Cambridge, MA, U.S.A.For contributions to ultrafast optics

Arthur LoweryMonash University, Dept. Electrical & Computer Systems Eng. - Victoria, AustraliaFor leadership in computer modeling of op-tical communication systems

Paul McManamonAir Force Research Laboratory (AFRL/RYRT) - Dayton, OH, U.S.A.For contributions in optical phased array and laser radar

Klaus PetermannTechnische Universitat Berlin - Berlin, GermanyFor contributions to optical communications technology

Chi SunNational Taiwan University, Graduate Institute of Photonics and Optoelec-tronics - Taipei, TaiwanFor contributions to high resolution medical microscopy and nano ultrasonic imaging

Peter WinzerBell Laboratories, Alcatel-Lucent - Holmdel, NJ, U.S.A.For contributions to high-speed digital optical modulation in transport networks

News


News (cont’d)

2009 IEEE/LEOS Award Reminders!!The deadline for submitting nominations for the following awards is 30 April.William Streifer Scientific Achievement AwardEngineering Achievement AwardAron Kressel Award and Distinguished Service AwardIn order to facilitate the nomination procedure, nomination forms are found on pages 28 and 29.

IEEE/LEOS William Streifer Scientific Achievement AwardThe IEEE/LEOS William Streifer Scientific Achievement Award is giv-en to recognize an exceptional single scientific contribution that has had a significant impact in the field of lasers and electro-optics in the past 10 years. It may be given to an individual or to a group for a single contribution of significant work in the field. No can-didate shall have previously received a major IEEE award for the same work. Candidates need not be members of the IEEE or LEOS.

IEEE/LEOS Engineering Achievement AwardThe IEEE/LEOS Engineering Achieve-ment Award is given to recognize an exceptional engineering contribution that has had a significant impact on the development of laser or electro-optic technology within the past 10 years. It may be given to an individual

or to a group for a single contribu-tion of significant work in the field. No candidate shall have previously received a major IEEE award for the same work. Candidates need not be members of the IEEE or LEOS.

IEEE/LEOS Aron Kressel AwardThe IEEE/LEOS Aron Kressel Award is given to recognize those individuals who have made important contribu-tions to opto-electronics device tech-nology. The device technology cited is to have had a significant impact on their applications in major practical systems. The intent is to recognize key contributors to the field for de-velopments of critical components, which lead to the development of systems enabling major new services or capabilities. These achievements should have been accomplished in a prior time frame sufficient to permit evaluation of their last impact. The work cited could have appeared in the

form of publications, patents, products, or simply general recognition by the professional community that the indi-vidual cited is the agreed upon origi-nator of the advance upon which the award decision is based. The award may be given to an individual or group, up to three in number.

IEEE/LEOS Distinguished Service AwardThe IEEE/LEOS Distinguished Service Award was established to recognize an exceptional individual contribution of service which has had significant ben-efit to the membership of the IEEE Lasers and Electro-Optics Society as a whole. This level of service will often include serving the Society in several capacities or in positions of significant responsibility. Candidates should be members of LEOS.

The list of previous winners and nomination forms can be found on the LEOS Home Page http://www.i-LEOS.org.

Call for Fellow NominationsOn the Lookout for a Few Good Fellows by Rosann MarosyIt’s not too early to nominate an IEEE senior member for the Fellow class of 2010. The deadline is 1 March 2009.

This prestigious group now numbers 6000 out of IEEE’s to-

tal of 375 000 members. While many view Fellows as visionar-ies, pioneers, technology leaders, or influential business executives, you probably know them as your friends or colleagues. So take the time to nominate someone you know in one of four Fellow catego-

ries: application engineer, educa-tor, research engineer, or technical leader.

To submit a nomination or learn more about these categories and the Fellow Program, visit the Fellow Web site at http://www.ieee.org/fellows


Send nomination information with supporting material to: IEEE/LEOS Awards Committee; 445 Hoes Lane; Piscataway, NJ 08854

Fax: +1 732-562-8434; email: [email protected] 11-07

Nomination Form forIEEE/LEOS Awards

Please check the appropriate award category:

Quantum Electronics (16 Feb deadline)

Engineering Achievement (30 April deadline)

Separate forms are available for the Distinguished Lecturer, Distinguished Service, Young Investigator, and John Tyndall Awards 1. Name of Nominee (for joint nominations, give the names, address information of the co-workers on a

second sheet. 2. Nominee’s Address

:xaF :enohP s’eenimoN .3 Email: 4. Proposed Award Citation (20 words or less) 5. On separate sheets attach: a. Statement of specific contribution(s) that qualify Nominee for Award, as well as other related

accomplishments (maximum of two pages). b. Nominee’s curriculum vita c. Endorsers: List the names, affiliations, addresses, and emails of individuals who have agreed to

write letters of support. (Minimum of three supporting letters required; maximum of five permitted. No more than five letters will be reviewed by the Committee. Letters may accompany nomination or be submitted directly to IEEE LEOS prior to the nomination deadline.) Letters of recommendation are to be considered confidential and are not to be released to anyone other than IEEE-LEOS awards staff.

6. Your name:

:xaF :enohP Email:

Aron Kressel (30 April deadline)

Streifer Scientific Achievement (30 April deadline)

News (cont’d)


Nomination Form forIEEE/LEOS Distinguished Service Award

Deadline: 30 April

1. Name of Nominee:

2. Nominee’s Address

3. Nominee’s Phone: Fax:

Email:

4. Proposed Award Citation (20 words or less)

5. Attach a description of the Nominee’s exceptional individual contribution of service that has had significant benefit to the membership of the IEEE Lasers & Electro-Optics Society as a whole. This level of service will often include serving the Society in several capacities or in positions of significant responsibility.

6. Your name:

:xaF :enohP

Email:

Send nomination information with supporting material to: IEEE/LEOS Awards Committee; 445 Hoes Lane; Piscataway, NJ 08854

Fax: +1 732-562-8434; email: [email protected]

7-06

News (cont’d)


2008 LEOS Best Student Paper Award RecipientsThe LEOS Best Student Paper Awards are open to students from universi-ties whose papers have been accepted for presentation at the LEOS An-nual Meeting. The top five finalists

receive certificates of recognition and monetary awards ranging up to $1000.

The results for the 2008 LEOS Best Student Paper Award are as follows:

1st Place – Hyejun Ra2nd Place – Liang (Luke) TangFinalist – Andrei FaraonFinalist – Seth A. FortunaFinalist – K. Shavitranuruk

The Young Investigator Award was established to honor an individual who has made outstanding technical contributions to photonics (broad-ly defined) prior to his or her 35th birthday. Nominees must be under 35 years of age on 30 September of the year in which the nomination is made. Candidates need not be members of the IEEE or LEOS. The deadline for nominations is 30 September.

The 2009 IEEE/LEOS Young In-vestigator Award will be presented to Aydogan Ozcan, “for his pioneer-ing contributions to non-destructive nonlinear material characterization techniques, near-field and on-chip imaging and diagnostic system.” The presentation will take place during the Plenary Session held on 3 June at CLEO/IQEC - Conference on Laser and Electro-Optics and the International Quantum Electronics Conference, 31 May–5 June, Balti-more Convention Center, Baltimore, Maryland, USA.

Aydogan Ozcan received his Ph.D. degree at Stanford University Electri-cal Engineering Department in 2005. After a short post-doctoral fellowship at Stanford University, he is appointed as a Research Faculty Member at Har-vard Medical School, Wellman Center for Photomedicine in 2006. Dr. Ozcan

joined UCLA in the summer of 2007, where he is currently leading the Bio- and Nano-Photonics Labo ratory (http://innovate.ee.ucla.edu/) at the Electri-cal Engineering Department. Prof. Ozcan’s research group is also part of UCLA California NanoSystems Insti-tute (CNSI), where he is serving as a member of the research committee.

Dr. Ozcan holds 11 US patents,

1 UK patent and another 9 pending patent applications for his inventions in nanoscopy, wide-field imaging, nonlinear optics, fiber optics, and optical coherence tomography. All of his patents are currently licensed by

Northrop Grumman Corporation, which is the leading defense company in US. Dr. Ozcan is also the co-author of more than 70 peer reviewed re-search articles in major scientific jour-nals and conferences.

Dr. Ozcan is serving in the Scien-tific Advisory Board of the Lifeboat Foundation, and is a member of the program committee of SPIE Photon-ics West Conference. He also serves as a panelist and a reviewer for National Science Foundation and for Harvard-MIT Innovative Technology for Medi-cine Program.

For his work on lensfree on-chip imaging and diagnostic tools, Prof. Ozcan received the 2008 Okawa Foundation Research Award, given by the Okawa Foundation in Japan. Prof. Ozcan also received the 2009 IEEE Lasers & Electro-Optics So-ciety’s (LEOS) Young Investigator Award. He is also the recipient of a National Science Foundation Award on “Biophotonics, Advanced Imag-ing, and Sensing for Human Health” for his on-chip plasmonic microsco-py work. Dr. Ozcan was also awarded the Presidential Fellowship from the Turkish Ministry of Education in 1996 (declined).

Dr. Ozcan is a member of IEEE, LEOS, OSA, SPIE and BMES.

2009 IEEE/LEOS Young Investigator Award Recipient: Aydogan Ozcan

Aydogan Ozcan

Career Section


The IEEE David Sarnoff Award was established in 1959 through agreement between the RCA Corporation and the American Institute of Electrical Engineers, and continued by the Board of Directors of the IEEE. In 1989, sponsor-ship of the award was assumed by the Sarnoff Corporation. It may be presented each year to an individual or team up to three in number for exceptional contributions to elec-tronics. For additional information on IEEE Technical Field Awards and Medals, to view complete lists of past recipients or to nominate a colleague or associate for IEEE Technical Field Awards and Medals, please visit http://www.ieee.org/awards.

The 2009 IEEE David Sarnoff Award will be presented to Yasuhiko Arakawa, Kerry John Vahala, and Kam Yin Lau “for seminal contributions to improved dynamics of quantum well semiconductor lasers.” The presentation will take place during the Plenary Session held on 24 March at OFC - Conference on Optical Fiber Communication, 22–26 March, San Diego Convention Center, San Diego, California, USA.

Yasuhiko Arakawa was born on 26 November 1952 in Aichi Prefecture, Japan. He obtained a B.S. degree in 1975 and a Ph.D. degree in 1980, respective-ly, from the University of Tokyo, both in Electronics Engineering.

Dr. Arakawa’s first pro-fessional association was with the University of To-kyo as an Assistant Profes-

sor in 1980. In 1981 he became an Assistant Professor at the University of Tokyo. In 1993, he was promoted a Full Professor of the University of Tokyo. He is now a Professor of Research Center for Advanced Science and Technology, the University of Tokyo and also the Direc-tor of Institute for Nano Quantum Information Electron-ics, the University of Tokyo. From 1984 to 1986 for two years, he was a visiting scientist of California Institute of Technology, staying with Professor Amnon Yariv. During his PhD, he worked on communication theory, propos-ing Extended Duo-binary Code matched to optical com-munication channels. When he joined the University of Tokyo, he switched his research field to photonic devices

based on quantum effects. His main achievement includes proposal of the concept of quantum dots and their ap-plication to quantum dot lasers (‘82), pioneering theo-retical and experimental work on quantum size effects on lasing dynamics in semiconductor lasers (‘84–‘86), dis-covery of exciton-polariton Rabi- vacuum oscillation in semiconductor nanocavity (‘92), discovery of continuum in density of states in quantum dots by PLE (‘92), the achievement of high temperature stability in high speed quantum dot lasers (‘04) , the first demonstration of single photon sources at telecommunication wavelength (‘04) and the highest operation temperature of 200 K achieved in all-solid single photon sources by using GaN quantum dots (‘06).

Dr. Arakawa is a Fellow of the IEEE, JSAP and IE-ICE. He is a member of Science Council of Japan. He has published about 400 papers in scientific journals and has given invited talks more than 200 times at international conferences. He has received a number of awards, includ-ing Young Scientist Award of International Symposium on Compound Semiconductors (1988), IBM Science Award (1992), ISCS Quantum Device Award (2002), IEEE/LEOS William Streifer Scientific Achievement Award (2004), Leo Esaki Prize (2004), The Wall Street Journal Technology In-novation Runner-Up Award (2006), Fujiwara Prize (2007) and Prime Minister Award (2007).

Dr. Arakawa and his wife, Kaoru, reside in Shin- Yurigaoka, Kawasaki, Japan. Ka oru is a Professor of Meiji University, working on signal processing and bio-information technology. They have two children, Akihiko and Hiroaki.

Kerry Vahala is Ted and Ginger Jenkins Professor of Information Science and Technology and Profes-sor of Applied Physics at Caltech. He also received his Ph. D. (85) in Applied Physics at Caltech.

His research on quantum well lasers predicted and later demonstrated dynami-cal improvements using engineered nanostructures

as active layers. These features contributed to the success of quantum well semiconductor lasers in communications

2009 IEEE David Sarnoff Award Recipients: Yasuhiko Arakawa, Kerry John Vahala, and Kam Yin Lau

Career Section (cont’d)

Yasuhiko Arakawa

Kerry Vahala


Career Section (cont’d)

“Nick” Cartoon Series

systems. Dr. Vahala has also pioneered the subject of high-Q microcavities, including applications to micro-scale Raman and parametric sources, cavity opto-mechanical phenomona, as well as cavity QED on-a-chip systems.

Dr. Vahala is a Fellow of the Optical Society of America, was the first recipient of the Richard P. Feynman Hughes Fellowship, and is also a recipient of an Alexan-der Von Humboldt Research Award. He received both the Presidential Young Investigator and Office of Naval Re-search Young Investigator Awards, has 28 patents, over 150 publications, and edited the book, “Optical Microcavities.” He was program co-chair for CLEO 99 and General Chair for CLEO 2001.

Kam Y. Lau received simultaneous B.S. /M.S. in 1978, and Ph.D. in 1981, all from Caltech in Electrical Engi-neering. Upon graduation, he joined Ortel Corporation as founding staff/chief scientist. His fundamental research in high-speed semiconductor laser dynamics provides the foundation for fiber-optic transmitter products leading to Ortel’s successes – its IPO and subsequent acquisition by Lucent/Agere.

Prof. Lau received the IEEE William Streifer Sci-entific Achievement and the Distinguished Lecturer Awards from IEEE LEOS in 1996 and the Nicho-las Holonyak Award from OSA in 2008. He was As-sociate Professor of E.E. at Columbia University from 1988–90, and a professor in the EECS department at U.C. Berkeley since

1990. He co-found LGC Wireless, Inc. (“L” of “LGC”). LGC delivers cost-effective in-building wireless cover-age and capacity solutions. With over 10,000 large-scale systems installed in .100 countries on every continent, its technology becomes de-facto industrial standard. LGC Wireless was acquired by ADC Telecom (Nasdaq : ADCT) in 2007.

In 2005 Prof. Lau assumed Emeritus status and retired from active duties at U.C. Berkeley.

Kam Y. Lau


The LEOS (Lasers and Electro Optics Society) Italian Chapter has been recognized twice this year. Firstly, in February, it was awarded Region 8 Chapter of the Year for Large Chapters (1001 Membership) by the CCSC Com-mission. The award was received in Malta by Silvano Do-nati, Founder and previous Chair of the Chapter, and now Italy Section Chair, on behalf of the present Chair Tiziana Tambosso. The award was presented by IEEE President L.Terman and by Region 8 President J.G. Remy.

Later in the year, when the LEOS Society announced the annual report, the Italian Chapter was recognized as the most prominent in terms of Membership Increase (118%), Conferences and workshops organized (12 in the year), and Special events, in particular the 30th LEOS anniversary celebrations, that the LEOS Italian Chapter held twice, in Rome University La Sapienza (January 30, 2008), with a DVD recording of the speeches and Rome University TV broadcasting, and in Pavia University (March 14, 2008).

LEOS Italian Chapter contributed to the First Winter Topical initiative with three different Topics proposed and chaired by Chapter Executive Committee members and Italian members. Most recent innovations introduced in

our Chapter have been: the electronic election of Officers through the web, using IEEE e-Notice support; the electron-ic newsletters for Italian LEOS members using e-Notice; two new awards to recognize the best paper published on LEOS journals by young researchers and the Distinguished Student award (see our web for details). We have also taken part in defining the Memorandom of Understanding between LEOS and the National Electronic Engineer Society AEIT.

Also worthy of mention is the serie of WFOPC Confer-ences initiated by T.Tambosso and S. Donati, on Fiber Optics and Passive Components. The WFOPC editions were run in Pavia in 1998 and 2000, Glasgow (by the Scotland Chapter) in 2002, Palermo (back to Italy) in 2005, and finally Taiwan (R.o.C., by the Taipei Chapter) in 2007. A second Confer-ence series, ODIMAP, on Optical Distance Measurements with Lasers and Applications, started in Nantes (France) in 1997, continuing at Pavia University in 1999 and 2001, Oulu (Finland) in 2004, and subsequently in Madrid (2006). All these Conferences were supported with Special Issues of Journals: in particular the IEEE Journal of Selected Topics in Quantum Electronics for WFOPC and Optical Engineer-ing, and Journal of Optics-A for the ODIMAP.

The Italian LEOS Chapter doubles as Chapter of the Year of both Region 8 and SocietyTiziana Tambosso – LEOS Italian Chapter Chair

LEOS Italian Chapter Secretary S.M. Pietralunga (left) receives the 2008 LEOS Chapter of the Year award from the hands of LEOS President J. Marsh (right).

LEOS Italian Chapter Chairperson T.Tambosso (left) with LEOS Italy Chapter Founder and Italy Section Chair S. Donati (right).

Membership Section


Larry A. BergmanAndre FranzenGeorge G. KingWei LiXiuling LiKonstantin L. Vodopyanov

Adam C. WardJunji YamauchiHongjun CaoPeter B. CatrysseGeorge C. ChenMark Cronin-Golomb

Wai Pang NgLuis PonceJohann P. ReithmaierNorman C. TienXiaoguang Zhang

Benefits of IEEE Senior Membership There are many benefits to becoming an IEEE Senior Member:

The professional recognition of your peers for technical and professional excellence• An attractive fine wood and bronze engraved Senior Member plaque to proudly display.• Up to $25 gift certificate toward one new Society membership.• A letter of commendation to your employer on the achievement of Senior member grade (upon the request of the newly • elected Senior Member.)Announcement of elevation in Section/Society and/or local newsletters, newspapers and notices.• Eligibility to hold executive IEEE volunteer positions.• Can serve as Reference for Senior Member applicants.• Invited to be on the panel to review Senior Member applications.•

The requirements to qualify for Senior Member elevation are a candidate shall be an engineer, scientist, educator, technical executive or originator in IEEE-designated fields. The candidate shall have been in professional practice for at least ten years and shall have shown significant performance over a period of at least five of those years.”

To apply, the Senior Member application form is available in 3 formats: Online, downloadable, and electronic version. For more information or to apply for Senior Membership, please see the IEEE Senior Member Program website:http://www.ieee.org/organizations/rab/md/smprogram.html

The following individuals were elevated to Senior Membership Grade thru Nov – Dec:

New Senior Members

With this recognition, the LEOS Italian Chapter, which is also celebrating its 10th anniversary in 2007, received a total of 7 awards: Most Improved Chapter 1998, Most Improved Chapter 1999, Chapter of the Year Society 2001, Most Innovative Chapter 2002, Chapter of the Year R8 2002, Chapter of the Year R8 2007, and Chapter of the Year Society 2008.

The Italian LEOS Chapter has been chaired by Tiziana Tambosso since 2002 (re-elected four times). Tiziana, of Tambosso & Associates, was formerly a research manager at Telecom Italia R&D Center (Torino).

For more details on the Italy Chapter activities see the website http://www.unipv.it/leos. T. Tambosso e-mail: [email protected] (for any question, suggestions and proposal of cooperation please do not hesitate to con-tact me) my website: http://www.studiotambosso.it

S. Donati (co-Chair of WFOPC 2007) in front of WFOPC 2007 Panel, at the Graduate Institute of Electrooptical Engineering (GIOE) of Taipei (Taiwan).

Membership Section (cont’d)


2008 LEOS Awards and RecognitionsJohn Marsh, LEOS President, recognized the recipients of the 2008 LEOS awards and several of our volunteers for their service to the Society. The awards were presented during the Awards Banquet at the LEOS Annual Meeting in Newport Beach, California, USA.

The IEEE/LEOS William Streifer Scien-tific Achievement Award was presented to Fumio Koyama, “for contributions to vertical cavity surface emitting semicon-ductor lasers and dynamic single-mode semiconductor lasers.”

The IEEE/LEOS Engineering Achieve-ment Award was presented to Kent D. Choquette, “for development of the mono-lithic selectively oxidized vertical cavity surface emitting laser.”

The IEEE/LEOS Distinguished Service Award was presented to James Coleman, “for contributions to and leadership in the area of publications.

LEOS Fellows

LEOS Fellow plaques were presented to A. Catrina Bryce and Han-Ping Shieh in recognition of their achievement to IEEE Fellow grade.

Conference Section

A. Catrina Bryce Han-Ping Shieh


Distinguished Lecturers

Board of Governors

John Marsh recognized Massaya Notomi and Jorge J. Rocca who completed their terms as LEOS Distinguished Lecturers.

Markus Amann, Carmen Menoni, Kent D. Choquette, and Hideo Kuwahara completed their terms as elected members of the LEOS Board of Governors.

Conference Section (cont’d)

Massaya Notomi Jorge J. Rocca


John recognized Steve A. Newton for his service to LEOS as VP of Finance and Administration, Filbert J. Bartoli for his service as Secretary/Treasurer, Selim Unlu for his service as Associate VP Membership & Regional Activities – Americas, and Chennupati Jagadish for his service as Associate VP Membership & Regional Activities – Asia & Pacific.

Chapter Awards

The Chapter of the Year award was presented to the Italy Chapter. The Benelux Student Chapter was awarded the Most Improved Chapter, the award for the Most Innovative Chapter was presented to the Santa Clara Chapter. The award for Largest Membership Increase was presented to the Ukraine Student Chapter, and the Senior Member Initiative Award was presented to the Montreal Chapter. Silvia Maria Pietralunga (Italy), Philippe Tassin (Benelux Student), and Brent Whitlock (Santa Clara Valley), accepted the awards for their chapters.


Steve A. Newton

Selim Unlu

Filbert J. Bartoli

Chennupati Jagadish


Graduate Student Fellowships

IEEE Awards

LEOS Staff at the 21st LEOS Annual Meeting in Newport Beach, California, USA.

The 2008 IEEE/LEOS Graduate Student Fellowship recipients.

William Gruver, IEEE Division X Director, presented the IEEE David Sarnoff Award to James Coleman, “for leadership in the de-velopment of highly reliable strained-layer lasers.”, the IEEE Eric E. Sumner Award to Thomas L. Koch, “for pioneering contributions to optoelectronic technologies and their implementation in optical communications systems.”, and IEEE Donald G. Fink Prize Paper Award to Thomas J. Naughton, Bahram Javidi, Osamu Matoba, Yann Frauel, and Enrique Tajahuerce, for their paper entitled, “Three-Dimensional Imaging and Processing Using Computational Holographic Imaging.”



The 4th International Conference on Advanced Optoelec-tronics and Lasers (CAOL 2008) was held September 29 – October 4, 2008 in Alushta, on the south coast of Crimea, Ukraine. Alushta is one of the best vacation places in the South Crimea, with a population of about 100,000 and a unique, salubrious climate. Yalta, another nearby famous Crimean city has numerous hotels and cultural attractions and is well known due to the historic Crimean (or Argono-aut) Conference held in Livadia Palace there towards the end of World War II. Among other historical places of Crimea is Bakhchisaray, the former Tatar capital where the famous Palace of the Crimean Khan is located.

The 2008 CAOL meeting was organized by the Ukraine LEOS chapter and the Student Chapter at Kharkov National University of Radio Electronics, in cooperation with three Ukrainian Universities: Kharkiv National University of Radio Electronics, V. N. Karazin Kharkiv National Univer-sity, and Taurida National V. I. Vernadsky University. Other organizing chapters include the University of Guanajuato, Mexico, (Campus Irapuato-Salamanca), the joint IEEE AP/MTT/ED/AES/GRS/NPS/EMB East Ukraine Chapter, and IRE OSA Student Chapter. The large number of organizers has enabled a new series of conferences started in 2002 by the Ukraine LEOS Chapter at the LEOS Chapter Meeting in Glasgow. This conference series has resulted in dissemi-nation of information among researchers in various regions of the world. CAOL has become a recognizable title and the conference has attracted contributors from many countries in Europe, North America, Australia, and Asia.

After the 3rd CAOL in 2006 in Guanajuato, Mexico, cooperation between the Ukraine LEOS Chapter, the Uni-versity of Guanajuato, and LEOS Vice-President Dr. Selim Ünlü, resulted in formation of a new LEOS Chapter in Guanajuato. This new and active chapter organized the “Photonics in Mexico” symposium held in Acapulco on July 19-23, 2008 as part of LEOS Summer Topicals 2008. The conference series was continued in Ukraine in 2008. Successful organization of 2008 meetings would not be possible without permanent interest and support of past LEOS Vice-President Dr. Katya Golovchenko and Summer Topicals Chair, LEOS Vice-President Dr. Dominik Rabus. Dr. Golovchenko played a key role in organizing Photonics in Mexico symposium and has lent invaluable support to the organization of CAOL 2008.

In spite of its small number of members, the LEOS Ukraine Chapter is growing and constantly generating new ideas directed at encouraging support of Ukraine scien-tists. Particular attention is given to young scientists and

students. This activity was recognized by made by LEOS through several awards, including Most Innovative Chapter (2000, 2007), Chapter with Largest Membership Increase (2001, 2002), and Most Improved Chapter (2003).

We organized 3 meetings in Alushta: 4th Conference “Advanced Optoelectronics and Lasers” (CAOL 2008); 9th Conference “Laser and Fiber Optical Networks Modeling” (LFNM 2008); and Workshop “Terahertz Radiation: Basic research and application (TERA 2008)”. This set of co-located meetings illustrates the effectiveness of the LEOS activities in Ukraine and Mexico. Overall, the three meet-ings attracted over 200 participants with 230 papers from 28 countries on five continents. LFNM was the first event of the LEOS Ukraine Chapter formed in 1998, and today that conference is the annual meeting in Ukraine in the area of laser physics and applied optics. Both LFNM and TERA supplement and extend the circle of the participants from the point of view of the application of theoretical methods and computer modeling of optoelectronic and laser systems as well as neighboring areas like terahertz technology. The TERA workshop is unique, because it is devoted to the new and topical area of THz optics and optoelectronics, where the combination of fundamental physics and its practical application is used to address the important problems of anti-terrorism and drug trafficking.

Overall, the topics of the conferences embraced physi-cal, mathematical, and technical problems of modern laser physics, photonics, optics and terahertz photonics. Papers on semiconductor nanoengineering, novel lasers, including quantum cascade and quantum dot lasers, photonic crystals and devices, nonlinear optics, optical measurements, wave

International Conference on Advanced Optoelectronics and Lasers

Opening session (Speaker: I. Sukhoivanov; Conference co-chairs: M. Pereira, V.A. Svich, V.A. Maslov, I.V. Dzedolik)



propagation and control in lasers and optical systems were presented. Other topics included laser radiation control, photonic crystals and devices, ultrabroadband systems, and data transmission devices, including those for application in optical computers. The conference proceedings included two volumes, one each for CAOL (464 pages) and LFNM (160 pages), and separate CD-ROM proceedings for TERA workshop. All of conference proceedings were published before the meetings.

During the week, participants had an opportunity to ex-change ideas during the sessions and in informal discussions in the garden of the conference hotel and at the banquet. Interaction between well-known scientists and students

(who constituted one-third of the participants) were espe-cially enjoyed. I would like to make special mention of the work of LEOS Student Chapter of the Kharkov National University of Radio Electronics, whose members were part of the Organizing Committee and not only worked 12 hours a day but also made a number of interesting presentations, the high level of which was noted by many participants of the conference.

Undoubtedly, the most important event of the confer-ence series was participation of LEOS Distinguished Lec-turer Prof. John O’Brien who gave a seminar on “Photonic

Discussion during the poster session between participants from Russia, Ukraine, Mexico

Best young speakers. 1st line: Yu. Pilgun (T.Shevchenko National Univ., Kiev); M. Klimenko (Univ. of Radioelectronics, Khark-ov); E. Samsonova (MGU, Moscow), G. Sharma (INRS- EMT, Canada) 2nd line: T. Isaac (University of Exeter, UK); G. Tkachenko (Univ. of Radioelectronics, Kharkov)


Organizing Committee after conference closing


Crystal Devices”. Other invited speakers included interna-tionally known scientists T. M. Benson, University of Not-tingham, UK, J. Abbate, Univ. of Naples Federico II Italy, and Prof. Bo Yong, Institute of Physics, Chinese Academy of Sciences, Beijing, China. Well-known scientific schools represented included The University of Leeds, University of Bristol, University of Salford, Sheffield Hallam Univer-sity (U.K.); The Institute of Photonic Sciences and ICREA (Spain); , Nonlinear Physics Centre, Australian National University, Canberra, Australia; R&D Institute of Physics NAS of Ukraine, Institute of Semiconductors Physics NAS of Ukraine (Ukraine); University of Guanajuato (Mexico), M.V. Lomonosov Moscow State University; Institute of Ap-plied Physics (Russia), National Institute of Materials Sci-ence, NIMS, Tsukuba, Institute of Science and Technology, AIST (Japan), and many others. Extremely interesting was the talk “Terahertz Quantum Cascade Lasers and Video-Rate THz Imaging” by MIT Prof. Qing Hu. The interest to that report and following discussions has allowed us to plan of the future development of TERA workshop and possible col-laborations as well.

We were happy to reach agreement on holding the next terahertz meeting in Turkey after an invitation by Dr. Tu-grul Hakioglu (Bilkent Universitesi, Ankara, Turkey) who will represent local organizers. Dr. Tugrul Hakioglu, Prof. Mauro Pereira, and I are actively preparing that workshop

whose topics of interest will be enlarged to cover mid-IR re-search http://smmo.org/TERA-MIR2009/. The number of invited speakers already today allows us to hope that TERA-MID Workshop will be one of the primary events in 2009.

We can say with great satisfaction that CAOL and LFNM are first-rate regular English-speaking conferences in the area of optoelectronics and laser engineering that have obtained international recognition. According to participants, CAOL is currently the only big conference on laser physics and optics in Ukraine and one of only two big conferences on optics and laser physics in the Commonwealth of Independent States.

As an organizer, I can say that the future optimal scheme for this conference series is alternation of separate conferences like LFNM, TERA, and a wide-topic conference CAOL. For this reason, 2009 will be devoted to preparation of TERA-MID Workshop in Turkey, and the 10th LFNM conference is planned for Ukraine in 2010. You are welcome to our meetings! All information about past and future conferences of this series can be found on these and other web sites:

http://caol.kture.kharkov.ua/http://caol.kture.kharkov.ua/eng/lfnm/lfnm_eng.htmlhttp://tera2008.kture.kharkov.ua/http://smmo.org/TERA-MIR2009/.

Igor A. SukhoivanovChair of the CAOL/LFNM/TERA

joint Organizing Committees


Visit the LEOS web site for more information:

www.i-LEOS.org


Call for PapersAnnouncing an Issue of the IEEE JOURNAL OF SELECTED TOPICS IN QUANTUMELECTRONICS on MetamaterialsSubmission Deadline: June 5, 2009IEEE Journal of Selected Topics in Quantum Elec-tronics invites manuscript submissions in the area of metamaterials, transformation optics and applications. Electromagnetic metamaterials is a rapidly developing field with remarkable potential for enabling new ways of controlling light from macro- to nano-scale. The purpose of this issue of JSTQE is to highlight the recent progress and trends in design, modeling, fabrication and applica-tions of metamaterials. Broad technical areas include (but are not limited to):

Novel metamaterials designs• Low-loss metamaterials: new approaches and • fabrication techniquesModeling and optimization tools • Broadband and tunable metamaterials • Optical nanocircuits • Light manipulation via transformation optics• Cloaking• Light concentrators and electromagnetic field • enhancement with metamaterialsPositive, negative, and near-zero guided wave structures • Super- and Hyper-lenses • Novel applications•

The Guest Editors for this issue are Vladimir Shalaev, Purdue University, USA; Natalia Litchinitser, State University of New York at Buffalo, USA; Thomas Klar, Technical University of Ilmenau, Germany; Na-der Engheta, University of Pennsylvania, USA, Ross McPhedran, University of Sydney, Australia, Ekaterina Shamonina, University of Erlangen-Nuremberg, Germany.

The deadline for submission of manuscripts is June 5, 2009; publication is scheduled for March/April of 2010.

Online Submission is Mandatory at: http://mc.manu-scriptcentral.com/leos-ieee. Please select the Journal of Selected Topics Of Quantum Electronics Journal from the drop down menu.

For inquiries please contact:Chin Tan-yanIEEE/LEOS Publications Coordinator445 Hoes Lane, Piscataway, NJ 08854 USAPhone: 732-465-5813, Email: [email protected]

For all papers published in JSTQE, there are voluntary page charges of $110.00 per page for each page up to eight pages. Invited papers can be twelve pages and Contributed papers should be 8 pages in length before overlength page charges of $220.00 per page are levied. The length of each paper is estimated when it is received. Authors of papers that appear to be overlength are notified and given the op-tion to shorten the paper. Additional charges will apply if color figures are required.

The following supporting documents are required during manuscript submission:

.doc manuscript (double columned, 12 pages for an 1) Invited Paper. Contributed paper should be double columned, 8 pages in length.) Bios of ALL authors are mandatory, photos are optional. You may find the Tools for Authors link useful: http://www.ieee.org/web/publications/authors/transjnl/index.htmlCompleted the IEEE Copyright Form. Copy and 2) paste the link below: http://www.ieee.org/web/publications/rights/copyrightmain.htmlCompleted Color Agreement/decline form.. (Please 3) email [email protected] to request for this form.).doc list of ALL Authors FULL Contact information 4) as stated below: Last name (Family name): /First name: Suffix (Dr/Prof./Ms./Mr):/Affiliation:/Dept:/Address:/Telephone:/Fax:/Email:/Alternative Email:

Publication Section


ADVERTISER’S INDEXThe Advertiser’s Index contained in this issue is compiled as a service to our readers and advertis-ers. The publisher is not liable for errors or omis-sions although every effort is made to ensure its accuracy. Be sure to let our advertisers know you

found them through the IEEE LEOS Newsletter.

Advertiser Page #

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California Scientific, Inc. . . . . . . . . . 20

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Optiwave Systems Inc . . . . . . . . . . . 33

General Photonics. . . . . . . . . . . . CVR4

LEOS Mission StatementLEOS shall advance the interests of its mem-bers and the laser, optoelectronics, and photo-nics professional community by:

providing opportunities for information • exchange, continuing education, and professional growth;publishing journals, sponsoring confer-• ences, and supporting local chapter and student activities;formally recognizing the professional • contributions of members;representing the laser, optoelectronics, • and photonics community and serving as its advocate within the IEEE, the broader scientific and technical community, and society at large.

LEOS Field of InterestThe Field of Interest of the Society shall be lasers, optical devices, optical fibers, and asso-ciated lightwave technology and their appli-cations in systems and subsystems in which quantum electronic devices are key elements. The Society is concerned with the research, development, design, manufacture, and ap-plications of materials, devices and systems, and with the various scientific and technolog-ical activities which contribute to the useful expansion of the field of quantum electronics and applications.The Society shall aid in promoting close cooperation with other IEEE groups and societies in the form of joint publications, sponsorship of meetings, and other forms of information exchange. Appropriate coopera-tive efforts will also be undertaken with non-IEEE societies.

MANAGEMENTJames A. VickStaff Director, Advertising Phone: 212-419-7767 Fax: 212-419-7589 [email protected]

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PRODUCT ADVERTISINGMidatlanticLisa Rinaldo Phone: 732-772-0160Fax: 732-772-0161 [email protected] NY, NJ, PA, DE, MD, DC, KY, WV

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Southeast Thomas FlynnPhone: 770-645-2944Fax: 770-993-4423 [email protected], NC, SC, GA, FL, AL, MS, TN

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So. California/Mountain StatesMarshall RubinPhone: 818-888-2407Fax: 818-888-4907 [email protected], AZ, NM, CO, UT, NV, CA 93400 & below

Europe/Africa/Middle East Heleen Vodegel Phone: +44-1875-825-700Fax: +44-1875-825-701 [email protected], Africa, Middle East

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