飛秒激光在空芯帶隙型微結構光纖中的傳輸特性研究.pdf

1、華中科技大學碩士學位論文飛秒激光在空芯帶隙型微結構光纖中的傳輸特性研究姓名：張繼皇申請學位級別：碩士專業(yè)：物理電子學指導教師：陸培祥20070521IIAbstractAnewtypeoffiberknownasmicrostructurefiberhasemergedinthepastseveralyears.Thesefibersareacterizedbywavelengthscalemicrostructuresdistribu

2、tingregularlyromlyinthecladdingregionrunningalongtheentirefiberlengthswhichhaveresultedinsomeunusualpropertiesunattainablefconventionalopticalfiberssuchasendlesssinglemodeflexibledispersionhighnonlinearphotonicbgap.There

3、femicrostructurefibershavegreatpotentialinthefieldofinfmationcommunicationbiomedicinetransducerultrashtpulselasertechnology.Hollowcephotonicbgapmicrostructurefiberisonekindofmicrostructurefiberswhichguidelightbyphotonicb

4、gap.Howeverthisfiberhaspreponderanceondeliveryultrashtpulselaser.whichenableitinthefieldofbiomedicine.Thepropagatingpropertiesofmicrostructurefibersareinvestigatedtheeticallyexperimentallyinthepresentdissertation.Hollowc

5、ephotonicbgapmicrostructurefiberissimulatedbyusingoftheeticalmethod.Firstlythephotonicbgapsofmicrostructurefiberarecalculatedbyusingoffullvectialplanewaveexpansionmethod.Thephotonicbgapsofdifferentcrystallatticeconstantd

6、ifferencebetweenhollowceallsolidPBGfibersareanalysed.Secondlyweusedthefiniteelementmethodtosimulatetheeffectivemodeindexdispersionpropertiesofhollowcephotonicbgapmicrostructurefibers.Propagatingoffemtosecondlaserpulseina

7、newstructurehollowcemicrostructurefiberisinvestigated.Thetransmissionspectralossofmicrostructurefiberaremeasuredonexperiment.Weresearchedtherelationsbetweenthespectrumofoutputpulsesthroughfibercelasercentralwavelengthlas

8、erpowerfiberlength.Itisdemonstratedthatnanojoulefemtosecondlaserpulsescoupledintotheaircepropagatewithnearlypreservedspectralprofilesthroughtheshterlengthfiber.Combiningtothepropertyofdispersionwegiveanalysisasfollows:Th

9、espectrumofoutputpulsesismainlyaffectedbyFourwaveMixingtheroleofselfsteepeninghigherderdispersionismehighlightedastheincrementofaveragepower.Thesecondarycesbetweenairholesinthecladdingofthisfibercanbeservedaswaveguidecha