超短脉冲光源及大模场光子晶体光纤研究

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1、天津大学硕士学位论文超短脉冲光源及大模场光子晶体光纤研究姓名：刘洋申请学位级别：硕士专业：物理电子学指导教师：贾东方20090501ABSTRACTUltra—shortpulsesource，whichisoneofthekeytechniquesinhi曲一speedopticalcommunicationsystem,hasbecomethehotspotinthecurrentresearch．Andwiththedevelopmentofhigh--powerfiberlaserandamplifier,l

2、arge··mode-·areaphotoniccrystalfiber(PCF)withlowbendinglossesareOfgreatimportancenow．Thepresenteddissertationfocusesonthegenerationofultra-shortpulseanddesignoflarge-mode-areaPCFwithlowbendinglossesbytheoreticalanalysisandexperiments，andthemaincontentsareasfoll

3、ows：1．Opticalpulsecompressiontechniques1)Anoveladiabaticsolitontechniquebasedonlossmanagementfibertransmissionlineisproposed．Whenthefiberlengthisset，thebestcompressingperformancecanbeachievedbycontrollingthepumppowercarefully．2)Anewopticalpulsecompressionmethod

4、onthebasisofquasi-nonlinearincreasingfiberconsistingofsingle—modefiber(SMF)，dispersion—shiftedfiber(DSF)andhighnonlinearfiber(HNLF)ispresented．Thisschemeiseasyrealizedinpracticebecausethefiberusedinthesimulationarecommercial．Moreover，itCanbecontrolledflexiblyby

5、simplychangingthegainofEDFA．3)Anovelcomb—likenonlinear铷ercompressorispresented．Itissimplestructured．andwithhigh-qualitycompressedpulse，whichhasarelativelysmallpedestal．2．Highpowernonlinearpolarizationrotationpassivelymode·lockedfiberlaser1)Operationprincipleofa

6、nonlinearpolarizationrotationpassivelymode-lockedfiberlaserisinvestigatedtheoreticallybysolvingtemporalmode-lockingequation．2)Basedonpolarizationadditivepulsemode-lockingtechnique，astable，self-startingmode—lockedpulsetrainat1．74MHzrepetitionratewithcentralwavel

7、engthof1564。lnm，pulse-widthof8．8psandspectralwidthof21。4nmisobtained。Theenergyofsinglepulseis14．64nJ．Theinfluenceofcouplingratioisexperimentallyinvestigated．3．Designoflarge-mode-areaPCFwithlowbendinglosses1)Thebasictheory，categoriesandtheresearchmethodofthePCF．

8、2)Themodefielddistribution,effectiverefractiveindex，effectivemodearea，numericalaperture(NA)andthemodepropertiesofnormalPCFarestudied．3)Anewdesignschemeoflarge—mode-areaPCFwi