Post on 13-Feb-2016
description
“区域光纤通信网与新型光通信系统”国家重点实验室
New Opportunities for Optical Phase-locked Loops in
Coherent PhotonicsLarry A. Coldren , Mingzhi Lu, Hyun-chul
ParkECE UCSB
“区域光纤通信网与新型光通信系统”国家重点实验室
Outline
Background• Coherent Optical Communication• Optical Frequency Synthesizer/Sweeper
Architecture of OPLL
Experiments and Results
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“区域光纤通信网与新型光通信系统”国家重点实验室
Coherent Optical Communication
Spring up in 1980s• Coherent receiver vs. IMDD
• Improve sensitivity • Longer reach between repeaters• Optical homodyne: Best power penalty performance
• OPLL prototypes • Phase error reduction/Synchronization
• LIMIT• Laser linewidth• Loop bandwidth• Stability: temperature, vibration, environment fluctuations
Refrigerated in 1990s• EDFA• WDM
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“区域光纤通信网与新型光通信系统”国家重点实验室
Coherent Optical Communication
2000s, Digitalization• Spectral efficiency• Full vector optical field• Linear, nonlinear effects introduced by long-distance propagation• Intradyne:
• High-speed ADCs• Sophisticated DSPs• Complicated algorithms
• Costly to design/fabricate/operate, Power consumption
2010s, revival• Enhanced sensitivity• Small size, low power • Sensor applications
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“区域光纤通信网与新型光通信系统”国家重点实验室
Optical Frequency Synthesizer/Sweeper
Optical signal processing• Microwave photonics:
– Microwave signal generation– Microwave Phase Detector/Shifter
• Military:– Beam-forming– LO distribution– Up/Down Conversion
Coherent Optical Measurement and Sensing Systems• FMCW LIDAR• OFDR• Ultra-accurate optical spectrum analyzers
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“区域光纤通信网与新型光通信系统”国家重点实验室
Optical Phase-Locked Loop
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OPLL Concept Optical: Laser Output Phase-Locked: Phase error (Phase noise)
Reduction / Synchronization Loop: Feedback
OPLL Structure
“区域光纤通信网与新型光通信系统”国家重点实验室
OPLL: Optical Phase Detector
Phase Detector Types• Homodyne / Heterodyne• Linear / Nonlinear
Linear Homodyne Detection Balanced loop
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“区域光纤通信网与新型光通信系统”国家重点实验室
OPLL: Optical Phase Detector
Other Detection Types Costas/Decision-driven loop SyncBit loop
Dither loop
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“区域光纤通信网与新型光通信系统”国家重点实验室
OPLL: Optical Voltage Controlled Oscillator
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OVCO techniques:
• Resonator mirrors tuning (by PZT)• Laser driving current
• Phase modulation• Acousto-optic modulation• SSB modulation
LaserPZT/Current control
V c
f LO
OVCO
Laser
V c
+
OVCO
ElectricalVCO
PM/AOM/MZM
f LO
f VCO
“区域光纤通信网与新型光通信系统”国家重点实验室
Optical Phase-Locked Loop
Requirement• Large loop bandwidth
– Bandwidth of OPD 、 OVCO– Short loop delay for stable operation
• Narrow laser linewidth• Insensitive to environment fluctuation • Small size• Low power• No crosstalk between phase-locking signal and data• Transparent link• No residual carrier transmission required
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“区域光纤通信网与新型光通信系统”国家重点实验室
Architecture of OPLL
Costas LoopHomodyne / HeterodyneLoop bandwidth: 1.1GHzPhase error variance: <0.03
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“区域光纤通信网与新型光通信系统”国家重点实验室
Architecture of OPLL
PIC: • SG-DBR laser• Optical Hybrid • four uni-traveling carrier PDs• 4.3 × 0.56 • 40 ps propagation delay
Size: 10 × 10 Loop delay: 120 ps
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EIC: • LIA• SSB Mixer• XOR and a delay line• 1.30 × 1.20 • 50 ps propagation delay
“区域光纤通信网与新型光通信系统”国家重点实验室
Architecture of OPFD
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SSB Mixer • Heterodyne• Frequency sweep (Range:1~20GHz)
SSB Mixer
PFD• Quadricorrelator Type• Pull-in range : 46GHz
“区域光纤通信网与新型光通信系统”国家重点实验室
Hybrid Loop Filter
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Type II 2nd Order Loop Filter
• High DC gain• OPA delay of 200ps
Feedforward capacitor• Phase compensation
Phase Margin =
“区域光纤通信网与新型光通信系统”国家重点实验室
Experiment and Result
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Locking 10MHz linewidth laser to 100KHz
“区域光纤通信网与新型光通信系统”国家重点实验室
Experiment and Result
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40Gbit/s coherent receiver using costas loop
“区域光纤通信网与新型光通信系统”国家重点实验室
Conclusion
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High bandwidth Small size and low powerLarge optical frequency synthesis rangeFor multiple applications
• Frequency-Modulated Continuous-Wave (FMCW) Light Detection and Ranging (LIDAR) systems
• Widely-and-fast-tunable ultra-narrow-linewidth lasers• Ultra-accurate optical spectrum analyzers
“区域光纤通信网与新型光通信系统”国家重点实验室
谢 谢!