光电子材料导论 非线性光学.ppt

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1、信息传输材料与技术－－－传输非线性Increasethetransmissioncapacityofadense-wavelength-division-multiplexing(DWDM)system：increasethetransmissiondatarateperwavelengthchromaticdispersionpolarization-modedispersionnonlinearity信息传输材料与技术－－－传输非线性increasethenumberofwavelengthswhilekeepingpropert

2、ransmissiongranularity.optical-nonlinearity-inducedsystemlimitations:XPM,SPM,FWMThreefundamentallimitingfactorsinU-DWDMSystemsinclude:1)variousrandomnoiseterms;2)fiberchromaticdispersion-inducedintersymbolinterference(ISI);3)optical-nonlinearity-induceddistortionandinterf

3、erence.MLMLaserSpectralOutputtypicalopticaloutputspectrumofanMLMlaserandthecorrespondingRMSspectralwidth.DispersionwithaNormalDFBLaserPolarizationModeDispersion（PMD）Polarizationmodedispersion(PMD)isanothercomplexopticaleffectthatcanoccurinsingle-modeopticalfibers.Single-m

4、odefiberssupporttwoperpendicularpolarizationsoftheoriginaltransmittedsignal.Figure1.Realfiberislikemanyretardationplatesinserieswithdifferentorientationsandbirefringence.Itisequivalenttoasingleretardationplatehavingslowandfastaxes,andaneffectivebirefringence.Anopticalpuls

5、ebroadensbecausethetwopolarizationcomponentstravelwithdifferentspeeds.(a)GeneralU-DWDMsystemmodel.(b)PeriodicallyamplifiedU-DWDMsystemmodelwithpostdispersioncompensationineveryamplifierstage.thenonlineareffectshavebecomeevenmoreimportantsincethedevelopmentofEDFAandWDMsyst

6、ems.Theoriginofthenonlinearitiesistherefractiveindexoftheopticalfiber,varywiththeintensityofopticalsignal.Althoughtheindividualpowerineachchannelmaybebelowthelevelneededtoproducenonlinearities,thetotalpowersummedoverallchannelscanquicklybecomesignificant.Thecombinationofh

7、ightotalopticalpowerandlargenumberofchannelsatcloselyspacedwavelengthsisasourceformanykindsofnonlinearinteractions.Thenonlineareffectscanbedividedintotwocategories.duetheinteractionoflightwaveswithphonons.ItcontainstwoimportantnonlinearscatteringeffectsSRSandSBS.Theeffect

8、sthatarerelatedtotheKerreffect,theintensitydependenceonthenonlinearrefractiveindexoftheopticalfi