Theory of burst-mode receiver and its applications

590JOURNALOFLIGHTWAVETECHNOLOGY,VOL.15,NO.4,APRIL1997TheoryofBurst-ModeReceiverandItsApplicationsinOpticalMultiaccessNetworksChaoSu,Lian-KuanChen,andKwok-WaiCheung,SeniorMember,IEEEAbstract—Inthispaper,aunifiedtheoryforthenewlydevel-opedopticalburst-modereceiverispresented.Basedonthisthe-ory,ananalysisoftheperformanceofthereceiverisgivenboththeoreticallyandexperimentally.Thetheoreticalmodelagreeswellwiththeexperimentalresults.Thistheorycanquantitativelyexplainthebiterrorrate(BER)performanceofburst-modere-ceivers.Severalpotentialapplicationsofburst-modereceiversarealsoillustrated,includingapplicationsinsupervisorysystemforerbium-dopedfiberamplifier(EDFA)trans-oceanicopticallinksandvarioushigh-speedall-opticalmultiaccesspacketnetworks.I.INTRODUCTIONTHEnext-generationopticalnetworkswilllikelyrequirefastpacketswitching(e.g.,ATM)tosupportmultimediaapplications,andanultrahightransmissionspeedisverydesirable.Asthebitrateincreasestobeyondwhatelec-tronicprocessingcancomfortablyhandle,itisincreasinglydesirabletoreducetheamountofregenerativeelectronicprocessingateachnode.Recentadvancesinfiber-optictech-nology(e.g.,erbium-dopedfiberamplifier(EDFA),high-speedtimemultiplexing/demultiplexing,highdensitywavelengthdivisionmultiplexing(WDM)devices,opticaltunablefilter,etc.)havepromptedresearcherstoenvisionafutureall-opticalnetworkthatiscapableofsupportingmultipleaccessandservicesatveryhighbitrate.Intheseall-opticalmultiaccessnetworks,anynodecanuseadesignatedtimeslottosendapackettosomeothernodes.Averysignificantfeatureoftheseall-opticalmultiaccessnetworkwhichisdifferentfromconventionalpoint-to-pointlinksisthattheamplitudeandphaseofthereceivedpacketscanbequitedifferentfrompackettopacketduetodifferentfiberattenuationandthechromaticdispersioncausedbythevariationofthetransmitters’wavelengths.Theamountofamplitudeandphasevariationsbetweentwoburstydatapacketscanbeupto20dBand360.Conventionalreceiversarenotsuitableforburst-modeoper-ationbecausetheycannotinstantaneouslyhandlethedifferentManuscriptreceivedAugust14,1995;revisedAugust15,1996.ThisworkwassupportedbytheUniversityGrantCommitteeofHongKongunderRGCGrantCUHK499/95E.TheworkofC.SuwassupportedbyaPostdoctoralFellowshipfromtheChineseUniversityofHongKong.C.SuwaswiththeDepartmentofInformationEngineering,TheChineseUniversityofHongKong,Shatin,N.T.,HongKong.HeisnowwithQPSTechnologyInc.,Dorval,P.Q.,Canada.L.-K.ChenandK.-W.CheungarewiththeDepartmentofInformationEngineering,TheChineseUniversityofHongKong,Shatin,N.T.,HongKong.PublisherItemIdentifierS0733-8724(97)02687-X.arrivingpacketswithlargedifferenceinopticalpowerandphasealignment.Itisthereforenecessarytodesignreceiverswhichcanadapttothevariationinopticalpowerandphasealignmentonapacket-by-packetbasis.Thesetypesofre-ceiversarecalledburst-modereceivers.Theburst-modereceiverwasfirstrealizedbyOtaandSwartz[1],[2]forhigh-speedopticaldatatransmissionsys-tems.Byusingafewpreamblebitsinthedatastreamtodeterminethedetectionthresholdforthesubsequentburst,adc-coupledburst-modeopticalreceiverwithanautomaticthresholdcontrolcircuitwasrealized[2].Thereceiversen-sitivitywas37.5dBm[biterrorrate(BER)109]atabit-rateof900Mb/swithadynamicrangeof23dB.In[3],anovelhighspeedPINHBTmonolithicphotoreceiverwasdemonstratedforbothcontinuousandburst-modeformat.Themeasuredsensitivitieswere21.5and18.6dBmat2.5and5Gb/s,respectively,undercontinuousmodeoperation.Apowerpenaltyof1.5dBforburst-modeoperationwasalsoobservedbutunexplained.TherearetwointrinsiceffectsthatdegradetheBERperfor-manceofburst-modereceivers.FirstistherandomGaussiannoisewhichisalwayspresentatthereceiverthataffectsthedeterminationofthedecisionthresholdandintroducessensi-tivitypenalty.ThisproblemwasfirstaddressedbyEldering[4]whocomputedtheBERpenaltyduetoGaussiannoiseduringthedeterminationofthresholdsettingfromthepreamblefield.Amoreaccuratetheoreticalmodelwasprovidedin[5].Thesecondeffectcomesfromthefinitecharging/dischargingtimeoftheadaptivethresholddetectioncircuitryinthereceiver[6].Weprovideaunifiedframeworkinthispapertostudytheinteractionofthesetwoeffects.TheresultshowsthattheBERpenaltyisrelativelyindependentofthelengthofthepreamblefieldwhenthedischargingtimeisfinite.Thiscontrastsquitesharplywiththeresultin[4]whenthedischargingtimeisinfinite.Burst-modereceiversareverysuitableformanyhigh-speedopticalmultiaccessnetworkapplicationsusingregenerativeornonregenerativepackettransmissions.Forexample,thereceiverscanbeemployedinpassiveopticalnetworks[(PON)treetopologyusingtimedivisionmultipleaccess(TDMA)],opticalbusnetworks,WDMAopticalstarnetwork,multi-channelparallelopticaldatalink,supervisorysystemforundersea/long-hauledEDFAtransmissionsystems,etc.Foralltheseapplications,therequirementsfortheburst-modereceiversareasfollows:0733–8724/97$10.001997IEEESUetal.:THEORYOFBURST-MODERECEIVER5911)largedynamicrangetoallownetworkflexibility;2)fastresponsetimetoimprovedetectionofshortpacketorburstdata;3)simplicityandrobustnesstoimprovenetworkreliability.Thispaperisdividedintotwoparts.Inthefirstpart,wepresentaunifiedframeworktoexplaintheBERperformanceof