ITUT G667.docx

ITUT G667.docx

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ITUTG667

INTERNATIONALTELECOMMUNICATIONUNION

ITU-T

G.667

TELECOMMUNICATION

STANDARDIZATIONSECTOR

OFITU

（12/2006）

SERIESG:

TRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKS

Transmissionmediacharacteristics –Characteristicsofopticalcomponentsandsubsystems

Characteristicsofadaptivechromaticdispersioncompensators

CAUTION!

PREPUBLISHEDRECOMMENDATION

ThisprepublicationisanuneditedversionofarecentlyapprovedRecommendation.It willbereplacedbythepublishedversionafterediting.Therefore,therewillbedifferencesbetweenthisprepublicationandthepublishedversion.

FOREWORD

TheInternationalTelecommunicationUnion（ITU）istheUnitedNationsspecializedagencyinthefieldoftelecommunications.TheITUTelecommunicationStandardizationSector（ITU-T）isapermanentorganofITU.ITU-Tisresponsibleforstudyingtechnical,operatingandtariffquestionsandissuingRecommendationsonthemwithaviewtostandardizingtelecommunicationsonaworldwidebasis.

TheWorldTelecommunicationStandardizationAssembly（WTSA）,whichmeetseveryfouryears,establishesthetopicsforstudybytheITUTstudygroupswhich,inturn,produceRecommendationsonthesetopics.

TheapprovalofITU-TRecommendationsiscoveredbytheprocedurelaiddowninWTSAResolution 1.

InsomeareasofinformationtechnologywhichfallwithinITU-T'spurview,thenecessarystandardsarepreparedonacollaborativebasiswithISOandIEC.

NOTE

InthisRecommendation,theexpression"Administration"isusedforconcisenesstoindicatebothatelecommunicationadministrationandarecognizedoperatingagency.

CompliancewiththisRecommendationisvoluntary.However,theRecommendationmaycontaincertainmandatoryprovisions（toensuree.g.interoperabilityorapplicability）andcompliancewiththeRecommendationisachievedwhenallofthesemandatoryprovisionsaremet.Thewords"shall"orsomeotherobligatorylanguagesuchas"must"andthenegativeequivalentsareusedtoexpressrequirements.TheuseofsuchwordsdoesnotsuggestthatcompliancewiththeRecommendationisrequiredofanyparty.

INTELLECTUALPROPERTYRIGHTS

ITUdrawsattentiontothepossibilitythatthepracticeorimplementationofthisRecommendationmayinvolvetheuseofaclaimedIntellectualPropertyRight.ITUtakesnopositionconcerningtheevidence,validityorapplicabilityofclaimedIntellectualPropertyRights,whetherassertedbyITUmembersorothersoutsideoftheRecommendationdevelopmentprocess.

AsofthedateofapprovalofthisRecommendation,ITU[had/hadnot]receivednoticeofintellectualproperty,protectedbypatents,whichmayberequiredtoimplementthisRecommendation.However,implementersarecautionedthatthismaynotrepresentthelatestinformationandarethereforestronglyurgedtoconsulttheTSBpatentdatabaseathttp:

//www.itu.int/ITU-T/ipr/.

©  ITU  2006

Allrightsreserved.Nopartofthispublicationmaybereproduced,byanymeanswhatsoever,withoutthepriorwrittenpermissionofITU.

ITU-TRecommendationG.667

CharacteristicsofAdaptiveChromaticDispersionCompensators

Summary

ThisRecommendationcontainsparametersanddefinitionsfordevicesprovidingadaptivechromaticdispersioncompensation.Thesedevicesareneededfortransmissionanddetectionofopticalsignalsinasystemexhibitinghighlevelsdynamicvariationofchromaticdispersionwhichwouldotherwiseimpairsystemoperation.Singleandmultichannellineadaptivedispersioncompensatorsaredescribed,aswellassingleandmultichanneladaptivedispersioncompensatingtransmittersandreceiverswhichmaycompriseelectricaloropticalformsofchromaticdispersioncompensation.Informationonsinglechannelandmultichanneladaptivechromaticdispersioncompensationimplementation,aswellasprinciplesofadaptivedispersioncompensation,canbefoundininformativeappendices.

1Scope

ThisRecommendationcontainsparametersanddefinitionsfordevicesprovidingAdaptiveChromaticDispersionCompensationneededfortransmissionanddetectionofopticalsignalsinasystemexhibitingdynamicvariationofchromaticdispersion.TheAdaptiveDispersionCompensatingdevicesdescribedincludebothsingleandmulti-channelapplications.ThisRecommendationdefinesrequirementsandkeyparametersforAdaptiveDispersionCompensators（ADC）.ThisrecommendationdistinguishesLineAdaptiveDispersionCompensatorsfromAdaptiveDispersionCompensatingtransmittersandreceiverswhichmaycompriseelectricalaswellasopticalformsofChromaticDispersionCompensation.

2References

ThefollowingITU-TRecommendationsandotherreferencescontainprovisions,which,throughreferenceinthistext,constituteprovisionsofthisRecommendation.Atthetimeofpublication,theeditionsindicatedwerevalid.AllRecommendationsandotherreferencesaresubjecttorevision;usersofthisRecommendationarethereforeencouragedtoinvestigatethepossibilityofapplyingthemostrecenteditionoftheRecommendationsandotherreferenceslistedbelow.AlistofthecurrentlyvalidITU-TRecommendationsisregularlypublished.

ThereferencetoadocumentwithinthisRecommendationdoesnotgiveit,asastand-alonedocument,thestatusofaRecommendation.

2.1NormativeReferences

-ITU-TRecommendationG.650.2（2005）,Definitionandtestmethodsforstatisticalandnon-linearrelatedattributesofsinglemodefibreandcable.

-ITU-TRecommendationG.652（2003）,Characteristicsofasingle-modeopticalfibrecable.

-ITU-TRecommendationG.653（2003）,Characteristicsofadispersion-shiftedsingle-modeopticalfibrecable.

-ITUTRecommendationG.654（2004）,Characteristicsofacut-offshiftedsinglemodeopticalfibreandcable.

-ITU-TRecommendationG.655（2003）,Characteristicsofanon-zerodispersion-shiftedsingle-modeopticalfibreandcable.

-ITU-TRecommendationG.656（2004）,Characteristicsofafibreandcablewithnon-zerodispersionforwidebandtransport.

-ITU-TRecommendationG.661（1998）,Definitionandtestmethodsfortherelevantgenericparametersofopticalamplifierdevicesandsubsystems.

-ITU-TRecommendationG.662（1998）,Genericcharacteristicsofopticalamplifierdevicesandsubsystems.

-ITU-TRecommendationG.665（2005）,GenericCharacteristicsofRamanAmplifiersandRamanAmplifiedSubsystems.

-ITU-TRecommendationG.666（2005）,CharacteristicsofPMDcompensatorsandPMDCompensatingReceivers.

-ITU-TRecommendationG.671（2005）,Transmissioncharacteristicsofopticalcomponentsandsubsystems.

-ITU-TRecommendationG.694.1（2002）,SpectralGridsforWDMApplications:

DWDMFrequencyGrid.

2.2InformativeReferences

-ITUTRecommendationG.Sup39（2003）,Opticalsystemdesignandengineeringconsiderations.

-ITUTRecommendationG.959.1（2006）,Opticaltransportnetworkphysicallayerinterfaces.

3Termsanddefinitions

3.1Definitions

ThisRecommendationdefinesthefollowingterms:

3.1.1ADCtransmitter:

anopticaltransmittercontainingadaptivechromaticdispersioncompensationfunctionality.

3.1.2ADCreceiver:

anopticalreceivercontainingadaptivechromaticdispersioncompensationfunctionality.

3.1.3Dispersioncompensationparameter:

thisparameterdependsonthetypeofdispersioncompensationdevice,anddescribestheachievabledispersioncompensationperformanceofanADC.

ForanADCtransmitter,thetransmissionperformancerelatedtodispersionoftheADCtransmittercanbechangedadaptivelyaccordingtothedispersionchangeoftheopticaltransmissionlinkinwhichitisoperating.ThedispersioncompensationparameteristhedispersionaccommodationvalueoftheopticaltransmittersignalthatcanbeachievedbytheADCtransmitteroverthechannelfrequencyrange.

ForalineADC,thedispersioncompensationvaluebetweentheinputportandtheoutputportofthelineADCcanbechangedadaptivelyaccordingtothedispersionchangeoftheopticaltransmissionlinkinwhichthelineADCisoperating.ThedispersioncompensationparameteristhedispersioncompensationvaluebetweentheinputportandtheoutputportthatcanbeachievedbythelineADCdeviceoverthechannelfrequencyrange.

ForanADCreceiver,thedispersiontoleranceofthereceivercanbechangedadaptivelyaccordingtotheresidualdispersionvalueoftheopticaltransmissionlink.ThedispersioncompensationparameteristheacceptableresidualdispersionvalueoftheopticalinputsignaltotheADCreceiveroverthechannelfrequencyrangewhiletheBERremainslowerthanthespecifiedlimit.

3.1.4Dispersioncompensationtuningrange:

ThedifferencebetweenthemaximumvalueofthedispersioncompensationparameterandtheminimumvalueofthedispersioncompensationparameterofanADCdevice（measuredasps/nm）.

3.1.5Dispersioncompensationtuningtime:

ForanADCtransmitteroralineADC,thisisthetimedurationfromthestartofachangeofthedispersioncompensationparametertothetimeafterwhichitremainswithinthelimitsofthenewtargetvalueplusandminusthespecifiedtolerance.ThisisillustratedinFigure3-1.

Figure3-1/G.667–Illustrationofdispersioncompensationtuningtime

foranADCtransmitteroralineADC

ForanADCtransmitter,thespecifiedtoleranceisthespecifiederrorofthedispersionaccommodationvalue.

ForalineADCthetoleranceisthespecifiederrorofthedispersioncompensationvalue.

ForanADCreceiver,thedispersioncompensationtuningtimeisthetimedurationfromastepchangeoftheinputsignalresidualdispersiontothetimeafterwhichtheBERremainslowerthanthespecifiedlimit.ThisisillustratedinFigure3-2.

Figure3-2/G.667–IllustrationofdispersioncompensationtuningtimeforanADCreceiver

Note:

Thetunin