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Delivering 100G per wavelength with today’sDWDM infrastructureMotivation, Experiments and StandardsRIPE 55, Amsterdam

Michael Finkenzeller, IPT DWDM

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Agenda

Motivation and Some Background Information

100G transmission: Experiments and Trials

Standards: 100GbE, Carrier Ethernet Transport

Conclusion

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Historical Volume Growth AMS-IX

source: AMS-IX

Every 30 months traffic increased with factor 10.

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WDM - Wavelength Division Multiplexing

• Each “coloured” wavelength represents one WDM channel • Multiplexing of separate signals on same fiber

Glass Prism Glass Prism

White LightSpectrum

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Signal Quality Degradation in Optical Systems

Signal degradation

Attenuation Noise Non-linear effectsDispersionM

UX

DEM

UX

Chromatic dispersion tolerance decreasePolarization Mode Dispersion tolerance decreaseOSNR tolerance decreaseNon Linear Effects

Bit rate increase to 100Gb/s

• New transmission techniques• New optical modulation

schemes• New dispersion management

techniques• New components

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Agenda

Motivation and Some Background Information

100G transmission: Experiments and Trials

Standards: 100GbE, Carrier Ethernet Transport

Conclusion

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2006: 107 Gbit/s transmission over 160kmTransmission line:• 2x80-km field NZDSF, 19.7 dB attenuation per span• Direct optical 107 Gb/s generation and additional filtering• Electrical processing of 107 Gb/s in single chip after photo

diode• Q-factor: 10.4dB btb, 9.6dB after 160km

TXPre

comp80 km

Installed fiber

DCF80 kmInstalled

fiber

DCFRX

Optical Eye Diagramof 107Gbit/s signal

Photo of single chip clock & data recovery and 1:2 demux for 107Gbit/s

Field trial using ETDM sender and receiver.

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Fiber amplifiers

Error-correcting codes Phase

modulation

Electronic equalization

Years

Dis

tanc

e x

Cap

acity Today

Wavelength-division multiplexing

??

? ?

E

Technology Trends in 40G/100G

Enabling technologies:Modulation formats (DPSK, DQPSK)Polarization-Multiplexing (PolMux)

Coherent receivers

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Modulation formats: multiple bits per symbol

Δφ

0π

DPSK

(0,π)

(0,0)

(π,0)

(π, π)

POLMUX-DPSK

1 bit/symbol 2 bits/symbol

DQPSK

0

π/2

π

3π/2

Δφ

4 bits/symbol

φφ

POLMUX-DQPSK

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Experimental setup: • 10 channels with 111Gbit/s each (100GbE + EFEC) on a 50GHz grid• Alternative modulation format POLMUX-RZ-DQPSK• Completely electronic modulation and demodulation• 2375km of SSMF and 5 add-drop nodes• Coherent detection and equalization for polarization recovery and high chromatic

dispersion tolerance

As broad as 10G same infrastructure

usable!

2007: 10 x 111 Gbit/s transmission over 2375 km

Possible to use today’s 10G infrastructure for 100G/λ transmission

10-2

10-3

10-4

10-5

10-6

10-7

7.5

8

8.5

9

9.5

10

10.5

11

11.5

12

12.5

13

13.5

14

-1000 -750 -500 -250 0 250 500 750 1000Residual chromatic dispersion at receiver (ps/nm)

BER

20lo

g(Q

) dB

EFEC Limit

6x

95kmSSMF

Raman

WSS

AOM AOM

Post-compensation

Pre-compensation

LSPS

5x

DCF

RX

TX

DCF6x

95kmSSMF

Raman

WSS

AOM AOM

Post-compensation

Pre-compensation

LSPS

5x

DCF

RX

TX

DCF5x

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COHERENT 111-Gbit/s POLMUX-DQPSK(CP-QPSK)

111-Gbit/s POLMUX-(N)RZ-DQPSK transmitter: Polarization multiplexing

Intensity

Phase||Phase

0 0 3π/2π/2π/2 ππ 3π/23π/20 ππ/2

||

27.75G data HA

27.75G data HB27.75G clock

27.75G data VA

27.75G data VB

MZ

π/2

PBS

MZ

MZ

MZ π/2

POLMUX-(N)RZ-DQPSK receiver: Coherent detection

90°

Y

X 90°hyb

Clo

ck R

ecov

ery

Equa

lizat

ion

Car

rier r

ecov

ery

Erro

r cou

nter

Post-processed on PCXI

XQ

YQ

YI

X0°0°

90°hyb 90°

0°

X90°

Y0°

Y90°

LO PCPC

TDS6154C

Very narrow spectral width => Use of existing 50Ghz grid WDM systemsHigh spectral efficiency 4 bits per symbol (27,75Gbaud)Use of low spec 40-G electrical componentsChromatic dispersion and PMD are compensated electrically (1st time for 100Gb/s)Coherent detection allows electrical polarization de-multiplexing

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Native transport versus concatenated within DWDM layer

Native 40/100G (serial)

☺ optimal use of network capacity☺ easy service routing☺ easy to implement services in

meshed network

high reach might be available laterpotentially more regeneration

points

Concatenated nx10G (parallel)

☺ less optical impairments☺ more easy to obtain higher reach

routing as bundle of wavelengths necessarycongests network (especially

cumbersome in partially filled meshed network)latency cannot be avoideddoesn’t scale in OpEx/CapEx

Native transport is the better choice.Better scalability and simple maintenance: “One service, one port”

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Agenda

Motivation and Some Background Information

100G transmission: Experiments and Trials

Standards: 100GbE, Carrier Ethernet Transport

Conclusion

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100GbE: IEEE and ITU-T are different worlds.

IEEE World ITU-T World10M, 100M, 1G, 10G Interfaces

10G Interfaces

100M, 1G, 10G Interfaces

Distances 100m … 10/40km

155M, 622M, 2.5G, 10G, 40G Interfaces

10G / 40G in OTN Distances 2km - nx1000km

155M, 622M, 2.5G, 10G Interfaces

The IEEE world is short range and used factor 10 in the past.The ITU-T world is long range and used factor 4 in the past.

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Status 100GbE Standardization• Status IEEE 802.3 Higher-Speed Study Group (HSSG)

– Attendance predominantly interested in cost-efficient, mature transceiver alternatives for short-reach applications, transport networking vendors / service providers represent a minority. New: data center and server operators.

– Description of standard is scheduled for 2008, finalization for 2009/2010. – Data rate and de-skewing procedure are defined in study groups today.

• Status ITU SG15 Q6 / Q11: – Several OTU-4 proposals in G.709 are under discussion (111 - 112 Gb/s or 130Gb/s),

new revision of G.709 including 100GbE transport capability planned for Feb 2008.

Line InterfaceClient InterfaceLine Data Rate

(1λ), 2λ, 3λ100GbE 3 x 40Gb/s (9 ..12 x10Gb/s)

130Gb/s

1λ, 2λ100GbE (9-10 x 10Gb)111-112Gb/s

Data rate 130G would delay 100GbE products availability for 2 years.Close coordination is needed for 100G and 40G.

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Mapping of 10GbE: Example where standard didn’t much help …

For 10GbE two different line interfaces (over-clocking).

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AT&T, Verizon Have Optical WishesJUNE 08, 2007

… In a keynote on Wednesday, AT&T's Peter Magill said his company would need 100 Gig sooner rather than later.…Magill says that AT&T is committed to meeting bandwidth demands, however, and in an interview after his keynote, he said that AT&T would deploy pre-standard 100-Gig technology if it had to, as long as it made economic sense.

source: Light Reading, October 03, 2007

Pre-Standard 100G?

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Provide native End-to-End Ethernet ServicesNew 100GbE traffic will require an optimized Carrier Ethernet Transport (CET)

Subscriber/Service Access Metro Aggregation

DWDM Metro

CISCustomer IP Service

3Play VDSL

COSCustomerOptical Service

DSLAM

DWDM Core

3Play FTTH

PBB-TE/PBB T-MPLS

Access Switch

PBB-TECESCustomer Ethernet Service

Optical Transport

Edge Core

CIS PE

BRAS

3P-PE

IMS

IP Edge

IP/MPLS Core

Routing

Application

Carrier Ethernet Transport

Multilayer optim

ization

Offload core IP Routers of transit traffic

IP/MPLS routers just were really required

• DWDM infrastructure will transport 100GbE native interfaces => New transmission techniques to use existing WDM infrastructure

• Evolve from point-to-point DWDM to an optical meshed network with PXC & ROADM• Introduce GMPLS control plane in transport layer to optimize operation

R&D effortsR&D efforts

Use cost-effective L1

optical switching

where possible

Combine L2 & L1technologies for a cost-effective connection-oriented switching for

Carrier Ethernet Transport (CET)

PBB-TE/PBB (IEEE) T-MPLS (ITU-T)

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Agenda

Motivation and Some Background Information

100G transmission: Experiments and Trials

Standards: 100GbE, Carrier Ethernet Transport

Conclusion

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Conclusion

• Demand for 100G is real.– IP based applications are main driver.– Main payload will be Ethernet based services.

• 100G: Technology is on the right track.– Operation of 100G native on 10G infrastructure is feasible.– 100GbE standardization is key factor for products in 2010.

• Standardization Issues– Transport: client side and line side have to be synchronized– Carrier Ethernet Transport (CET) provides simplification and cost

savings for future

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Thank you …

… Questions?