100G技术中的光电器件.ppt

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1、Xun Li,Department of Electrical and Computer,Engineering,McMaster University,Optoelectronic Devices for 100G,Technology,100G Market and Technology ReadinessTransmission Schemes and ComparisonsOptoelectronic Devices for DP-QPSK/DQPSK Systems,Optoelectronic Devices for OFDM SystemsConclusion,Outline,D

2、efinition of 100G technology,100G transport:long-distance communication links,withmetro,regional,and long-haul DWDM networks sending dataat 100 Gbps over several thousand km through existing10G/40G infrastructures,100G Ethernet:links among routers,servers,and switches indata-center environments over

3、 shorter distances up to 40 km,While both technologies involve different optical,components and network architectures,both are necessaryfor faster computer connectivity,speedier data transport,and increased bandwidth.,100G transport standards:the Optical Internetworking Forum,(http:/,100G Ethernet s

4、tandards:in development by the IEEE,p802.3ba Task Force(http:/www.ieee.org/),100G Market and Technology Readiness,Increase in the volume of communicationtraffic comes from the spread of new,services such as cloud computing and on-line streaming,Qwest Communications internet traffic was,doubling ever

5、y 16 months in 2008,Facebook needs 100Gbps core switching justto keep up with the millions of new Facebookusers being added each week to the current300 million active users,NYSE:needs 100Gpbs immediately,AMS-IX:peak traffic reaches 600Gpbs already,100G Market and Technology Readiness,Verizon has dep

6、loyed the world 1st 100Gbpssystem over existing fibers originallyconditioned for 10Gpbs,100Gbps test bed has been established atGeorgia Institute of Technology(http:/www.100g.gatech.edu/),100G Market and Technology Readiness,Transition from 10G to 100G,Robustness against distortion 10G and 100G,abou

7、t the same,Enabling technologies:,From OOK to QPSK/DQPSK-highest SNRtolerance,Polarization-multiplex-no improvement possibleCoherent detection and DSP-space forimprovement,More efficient FECs-space for improvement,100G Market and Technology Readiness,Choices on the implementation of 100G,WDM,single

8、carrier,OFDM,High or low level constellations(high high spectra,efficiency,low symbol rate;low high noisetolerance,long transmission range),Star or square constellations(star better phasenoise tolerance,usually optimal in the sense that thedistance between the constellation points ismaximized for a

9、given energy,but difficult to,modulate and demodulate;square better ASE noisetolerance,sub-optimal on the constellation pointdistance but easy to modulate and demodulate),Blind or pilot-assistant equalization,100G Market and Technology Readiness,In 100G systems/networks,chromatic dispersion(CD)incre

10、ases 100 times,PMD increases 10times.Therefore,traditional OOK-DD schemewont work for,EDC reaches its limit in 10G systems already,hardware dispersion compensator has been installed in,fiber-links,The DWDM grid has been set at 50GHz,whichcannot accommodate the baseband of 100Gpbssignal in its origin

11、al form,Photonic cross-connects(PXC)set up limit tobandwidth as well,Modulation scheme with higher bandwidthefficiency(e.g.,QAM)has to be introduced toreduce the 100Gbps signal transmissionbaseband,Transmission Schemes and Comparisons,WDM,i.e.,10 10Gpbs,low bandwidth efficiency,cost divide at N 10Gp

12、bs scheme:N=4,Neither efficient,nor cost-effective in100G technology,Transmission Schemes and Comparisons,OFDM signal generation:,Transmission Schemes and Comparisons,Modulation QPSK,or other,f(t)e-jat F(+a)OFDM Transmitter,DeOFDM,Transmission Schemes and Comparisons,Demodulation QPSK,or otherOFDM R

13、eceiver,OFDM,Advantages:,easily adapt to severe channel conditions withoutcomplex equalization,robust against narrow-band co-channel interferencerobust against ISI,high spectra efficiency,efficient implementation through FFT,low sensitivity to time synchronization errors,tuned sub-channel receiver f

14、ilters are not required(unlike conventional FDM),Transmission Schemes and Comparisons,OFDM,Disadvantages:,sensitive to fiber/device nonlinearity,sensitive to frequency synchronization problemshigh PAPR,need linear transmitter circuitry,which suffers frompoor power efficiency,loss of efficiency cause

15、d by cyclic prefix and/orguard interval,Transmission Schemes and Comparisons,OFDM Only suitable when the channelnonlinearity is negligible.Therefore,it is apromising technique for high data ratetransmission over short-range,e.g.,in100G Ethernet.,Transmission Schemes and Comparisons,Transmission Sche

16、mes and Comparisons,FECCD compensationPMD compensationElectrical equalizationCoherent detectionModulation format,Transmission Schemes and ComparisonsKey technologies involved:,Transmission Schemes and Comparisons,Transmission Schemes and Comparisons,DP-QPSK:,Developed on QPSK for mature 40G technolo

17、gy,Key feature in DP-QPSK modulation plusdigital-coherent-detection(DCD):,replace optical PLL by digital technology in,electronic domain,Transmission Schemes and Comparisons,Frequency stabilized,narrow linewidthDFB laser,Polarization rotator,controller,splitter/combiner,MZM,phase delay array,Optoele

18、ctronic Devices for DP-,QPSK/DQPSK Systems,Phase delay array,Optical time-domain Fourier transformer,Optoelectronic Devices for OFDM,Systems,*Frequency stabilization electricfeedback,*Linewidth narrowing optical feedback,DFB Laser,*Periodic symmetry break down*Curved waveguide,*Strongly confined wav

19、eguide,e.g.,SOI*SPP waveguideOther techniques,Polarization Rotator,Controller,Splitter/Combiner,Polarization Control in Waveguide,TM Mode with n21E1=n22E2,Cladding:area 2 with n2,Core:area 1 with n1Substrate:area 2 with n2TE Mode with E1=E2,Polarization Control in Waveguide,Polarization Control in W

20、aveguide,Polarization Control in Waveguide,Polarization Control in Waveguide,Discrete schemes(DPD and PDP),*Integrated scheme,Optical Time-Domain Fourier Transformer,Quadratic phasemodulator,f(t),f(t)*exp(-jaLt2),f(t)*exp(-jaLt2)exp(jaLt2),f(t)*exp(-jaLt2)exp(jaLt2)*exp(-jaLt2),(/aL)F(t/2aL),Quadrat

21、ic phase,f(t),modulatorf(t)exp(-jaLt2),f(t)exp(-jaLt2)*exp(jaLt2),(/aL)F(t/2aL),Quadratic phase,modulatorf(t)exp(-jaLt2)*exp(jaLt2)exp(-jaLt2),Optical Time-Domain Fourier TransformerTime Domain Fourier Transformer:Time Lens,Possible Applications of Time LensPulse compressionTime LensT-Switch and W-D

22、emultiplexer Exchange,Time LensTime Lens,Time LensTime Lens,Possible Applications of Time LensDispersion Compensator,Time Lens,Time Lens,Phase Modulator,Long Haul Fiber TransmissionH()=exp-j(2L/2)2-j(3L/6)3h(t)=expj(2L/2)(t/2al)2+j(3L/6)(t/2al)3,f(t),f(t)*FH(),F(t)H(t),F(t),f(t),Possible Application

23、s of Time LensDispersion Compensator,Time Lens,Long Haul Fiber Transmission,f(t),F(t),H()=exp-j(2L/2)2-j(3L/6)3Envelope DetectionTime Lensf(t)H(t)F(t)*h(t),f2(t),100G market is ready,Technology is getting mature,Working optical components currently arestill in discrete version,Great incentive on the evolution of opticalcomponents towards integrated version,Conclusion,