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Transcript of KM3NeTmeeting Pylos, Greece, 16-18 April 2007 1 of 12 Mar van der Hoek et al. electronic department...
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
1 of 12
Mar van der Hoek et al. electronic department
PROGRESS ON OPTICAL MODULATORS
FOR KM3NeT
Mar van der Hoek
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
2 of 12
Mar van der Hoek et al. electronic department
OUTLINE
P Optical modulators: a key component for KM3NeT
P The KM3NeT architecture and worldwide interest in WDM-PON
P Commercial modulators as used in telecom networks
P Impact of modulator type on KM3NeT photonic network architectureand transmission performance
P Progress on Electro Absorption Modulators (EAM)
P Progress on Thermally Poled Fibres (TPF)
P Planning for further theoretical work & experiments
P Conclusions
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
THE OPTICAL MODULATOR: A KEY COMPONENT FOR KM3NeT
‘CONTINUOUS WAVE’ REGIME(OPTICAL FEED CHANNEL)
‘MODULATED WAVE’ REGIME(OPTICAL RETURN CHANNEL)
CW- MW LASER MODULATOR DETECTOR
ELECTRICAL DATA INDATA OUT
POWER
TIME
On shore Submerged On shore
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
WORLD WIDE WDM-PON DEVELOPMENTS
MULTI
WAVELENGTH
SOURCE
WDM
DETECTOR
DOWNSTREAM: DATA (λ1) + CW LIGHT (λ2)
TO THE HOME
UPSTREAM: DATA-IMPRESSED MODULATED LIGHT (λ2)
TO THE HUB
OPTICAL UNIT:
DWDM FILTER + REFLECTIVE MODULATOR (+OPTIONAL AMPLIFIER)
WDM-PON:
WAVELENGHT DIVISIONAL MULTIPLEX- PASSIVE OPTICAL NETWORK
HUB
HOME
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
BASELINE FOR KM3NeT: ‘LOW’ COST – PROVEN TECHNOLOGY
COMMERCIAL SEMICONDUCTOR LASER / MODULATOR MODULE
PHOTONIC INTEGRATED CIRCUIT TECHNOLOGY
ADVANCED PACKAGING TECHNOLOGY and
CUSTOM PHOTONIC INTEGRATED CIRCUITS
Discussed during a visits to CIP
(Centre for Integrated
Photonics UK) and Technical
University Eindhoven, the Netherlands
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
EXAMPLE OF A COMMERCIAL LASER MODULE
LASER DIODE CHIP
OPTICAL ISOLATOR
WAVELENGTH LOCKER/ EAM MODULATOR
Millions of devices operational in telecom networks !!
MONITOR DIODE
200X400µm
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
ASSUME: 1: TYPICAL LASER FWHM LINEWIDTH: 5 MHz = 0,04 nm = 40 pm2: ACHIEVABLE FBG REFLECTION PEAK SHIFT = 40 pm @ Vmod=Vmax (e.g. 10-40V)3: POCKELS COEFFICIENT FOR THERMALLY / ELECTRICAL POLED
HYDROGEN LOADED FIBRE: 0.3...10? pm/V
PMT to DIGITALOUTPUTMODULE
METALWIRES
2 SIDE HOLES IN FIBRE TO ACCOMODATE METALWIRES
FIBRE BRAGGGRATING
Electrical / Thermal Poled SINGLEMODE FIBREOD=125 m
INPUT / LASERSPECTRUM
Vmod
NOVEL TYPE OF PHOTONIC MODULATOR FOR KM3NeT
ELECTRO-OPTICAL EFFECTS IN POLED FIBRES
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
POLED FIBER DEVICES AS REALIZED BY ACREO, SWEDEN
Technology
CoatingMetal: AuSn
Exposed electrode
Section free from metal
High pressure
High temperature
Metal-filled holes
Liquid metal
Splicing not possible
Contact from end (?)Side-polishing(!)
Wire bonding
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
High voltage
280 oC
Using a poled fiber for electro optical switching
3 dB 3 dB
Active arm
Reference arm
Fiber Mach-Zehnder
++
--
silicasilica
280 280 ooCCR. Myers, S. Brueck et al, Opt. Lett. 16, 1732 (1991)
Poling fused silica
Integrated MZI
With holes
SECOND ORDER NON LINEARITY OF FIBERS BY POLING
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
Functiongenerator
3 dB 3 dB
ns pulsegenerator
-10 -8 -6 -4 -2 0 2 4 6 8 10-40
-20
0
20
40
60
80
100
120
140
160
Time (nanoseconds)
Am
plitu
de (V
)
2,2 ns
-10 -8 -6 -4 -2 0 2 4 6 8 10-4
-3
-2
-1
0
1
2
3
4
5
6
Time(nanoseconds)
Opt
ical
pow
er o
utpu
t (m
W) 2,2 ns
Trigcw
Electrical Optical
TRAVELLING WAVE MODULATION
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
Increasing sensitivity by means of spectral displacement with voltage
Principle: laser light reflects on fiber grating index change shifts reflected wavelength intensity reflected changes with applied voltage slow drifts can be compensated with voltage
λlaser
Position
Wavelength
no voltagewith voltage small index change
3 dBInterferometer
Poled fiber with chirped grating
λlaser
phase detection
Large delay with small index change
Recent (theoretical) development
CHIRPED GRATING TO REDUCE MODULATOR DRIVE VOLTAGE
Options for phase modulation!
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
INPUT / LASERSPECTRUM
FBG REFLECTIONSPECTRUM SHIFT DUE TOe.g. TEMPERATURE
“PMT DATA”
REFLECTION OF CW INPUT LASERWAVELENGTH
MINIMUM OPTICALTRANSMISSION
“REGULATOR CIRCUIT”
SMALL AMOUNT OF LEAKAGE OF PEAKWAVELENGTH (e.g. -20 dB)
LOW-FREQUENCY REGULATORCIRCUIT MAINTAINS PEAK OF FBGREFLECTION CURVE COINCIDENT WITHINPUT LASER SPECTRUM
THIS COMPENSATES FOR SMALL DRIFTIN FBG REFLECTION PEAK AND/ORSHIFT OF INPUT LASER SPECTRUM
ALSO: THERMAL TUNING OF FBG PEAKAS OPTION FOR OPERATING POINTSTABILIZATION
NOT REQUIRED FOR CHIRPED
GRATING!!
UNIFORM GRATINGS FOR ALL DWDM
CHANNELS!!
CHIRPED GRATINGS:TOWARDS UNIFORM MODULATORS
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
CHARACTERISTICS OF POLED FIBER MODULATORS
• All fiber construction, compatible with KM3NeT fibers• Fusion splicing to network fiber: low loss, no air gaps• Low power consumption due to capacitive switching• Low polarization dependence• Wide wavelength range for switching• Small footprint• Proven technology for grating and poling process• Potential low cost
• -/- OPTICAL GAIN not yet integrated
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
CHALLENGES
FOR ELECTRO-ABSORPTION MODULATORS:• Electro-absorption modulators are already very mature• For KM3Net: optimized modulator / amplifier design• Reduction of optical loss• Integration of modulator with optical amplifier and
all-optical serialiser into a single hermetic module
FOR POLED FIBER MODULATORS• Reduce drive voltage to 2-3 V• Increase modulation speed to 10 Gb/s• Incorporation of optical gain
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
RESOURCES TO REALIZE KM3NeT OPTIMIZED MODULATORS
Joint european Program on Photonic Integrated
Components and Devices
•Companies
•Technical universities
•System integrators
• Photonic device design / modeling
•Device realization
•Device packaging
•Functional testing
KM3NeTmeeting Pylos, Greece, 16-18 April 2007
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Mar van der Hoek et al. electronic department
SOME CONCLUSIONS
• ELECTRO ABSORPTION MODULATORS: PROVEN TECHNOLOGY• EAMs ARE USED BY HUNDERDTHOUSANDS IN TELECOM• POLED FIBER MODULATORS: STILL A STRONG CANDIDATE,
OFFERING SPECIFIC ADVANTAGES FOR KM3NeT• RECENT PROGRESS: CHIRPED GRATING, OFFERING:
– LOWER DRIVE VOLTAGE: 2-3 V
– REDUCED MODULATOR LENGHT: 100 mm
– POTENTIAL: UNIVERSAL GRATING FOR ALL DWDM CHANNELS
– EASY SPLICING OF POLED FIBER TO NETWORK FIBER