华中科大光纤通信chapter 4 optical receivers (including chapter...

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1、华中科大光纤通信Chapter4OpticalReceivers(includingChapter...本文由zxc2857808贡献ppt文档可能在WAP端浏览体验不佳。建议您优先选择TXT，或下载源文件到本机查看。Fiber-OpticCommunicationTechnologyChapter4OpticalReceivers2010-6-25OE,HUST1Chapter4OpticalreceiversBasicConceptCommonPhotodetectorsReceiverDesignReceiverNoiseReceiverSe

2、nsitivitySensitivityDegradation2010-6-25OE,HUST2ConfigurationvoltageopticalsupplysignalO/Epre-amplifierautomaticgaincontroldecisioncircuitclockrecoveryLinearChannelDataRecoverydataamplifierfilterPINorAPDFrontEndRequirementshighsensitivityfastresponselownoiselowcost&highreliabi

3、lity2010-6-25OE,HUST3Simulation2010-6-25OE,HUST44.1BasicConcepts4.1.1DetectorResponsivityStimulatedabsorption:photonhν>Eg→anelectron-holepairPhotoncurrent:IP=RP,R:responsivityinQuantumefficiency:electrongenerationrateIp/qhvη===RphotonincidenceratePin/hvqR=Ip/Pin=ηq/hv≈ηλ/1.24λ

4、↑→R↑?hv

5、ode:Tr=(ln9)(τtr+τRC)τRC:timeconstantoftheRCcircuitτtr:transittimeofcarriers,τtr=2010-6-25W,Vd:driftvelocityVd8OE,HUSTBandwidthofaphotodiodef=[2π(τtr+τRC)]1W↑→η↑→τtr↑→Tr↑→f↓Trade-offbetweenη&fDarkcurrentPin=0,I=Id≠0,Id<10nACausedbystraylightorthermallygeneratedelectron-holepai

6、rs2010-6-25OE,HUST9Chapter4OpticalreceiversBasicConceptCommonPhotodetectorsReceiverDesignReceiverNoiseReceiverSensitivitySensitivityDegradation2010-6-25OE,HUST104.2Commonphotodetectors4.2.1p-nphotodiodesareversebiasedp-njunctiondiffusivecomponentphotoncurrentdriftcomponent2010

7、-6-25OE,HUST11thepresenceofadiffusivecomponentdistortsthetemporalresponseofaphotodiode.solution:decreasingthewidthsofthep-andn-regions;increasingthedepletion-regionwidth.2010-6-25OE,HUST124.2.2p-i-nphotodiodes2010-6-25OE,HUST13i-layer→highresistance→largeelectricfield→thedeple

8、tionregionthroughoutit→driftcomponentdominatesoverthediffusio