基于光折變體光柵的FBG波長解調(diào)技術(shù)研究.pdf

1、西北工業(yè)大學(xué)碩士學(xué)位論文基于光折變體光柵的FBG波長解調(diào)技術(shù)研究姓名：李繼鋒申請學(xué)位級別：碩士專業(yè)：光學(xué)指導(dǎo)教師：趙建林20050301西北工業(yè)大學(xué)碩士學(xué)位論文ResearchonwavelengthdemodulationtechniqueoffiberBragggratingbasedonphotorefractivevolumegratingAbstractAnovelwavelengthdemodulationtechnique

2、offiberBragggratingispresentedinthisthesisonbasisofadequateresearchonthediffractionpropertiesofphotorefractivevolumegrating.Wherethephotorefractivevolumegratingworksasafilteringcomponentbymakinguseofthewavelengthselectiv

3、itytorealizethelinearfilteringofBraggwavelengthsignalandachievethepurposeofwavelengthdemodulation.Comparedwiththeavailabledemodulationtechniquesthemethodpossessesmanymerits:diferentphotorefractivevolumegratingscanbeeasil

4、yandflexiblydesignedaccordingtopracticalrequirementssuchasthemeasurementresolutionandrangephotorefractivevolumegratingcanbethermallyorelectricallyerasedandcanberepeatedlyusedmultiplephotorefractivevolumegratingscanalsobe

5、recordedinthesamephotorefractivecrystaltorealizethewavelengthdemodulationsofmultiplesensingfiberBragggratingsthesimpleconfigurationandcheapcostarealsothemeritsofthiskindoffiberBragggratingsensorandsoon.Encirclingthedemod

6、ulationtechniquetheprincipalworkinthethesisisasfollows:(1)ThereflectivespectraoffibergratingsinsinglemodesilicafiberincludinguniformfiberBragggratinglongperiodicfibergratinglinearlychirpedfibergratingandapodizationfiberg

7、ratingarenumericallysimulatedandtherelationshipsbetweenthespectraandthelengthofgratingaswellastherefractiveindexmodulationareinvestigated.ThesensingpropertiesfortemperatureandstrainoffiberBragggratingaretheoreticallyanal

8、yzedandnumericallysimulated.(2)OnbasisoftheKogelnikscoupledwavetheorytheangleselectivityandwavelengthselectivityofphotorefractivevolumegratingaretheoreticallyanalyzed.Furthermorethephotorefractivevolumegratingsareexperim

9、entallyrecordedintheLiNbO3:Fecrystalswiththeholographicmethodandtheexperimentalresultsofangleselectivityarepresentedundertheconditionsofdiferentcrystalthicknessesandrecordingangles.(3)Anovelmethodformeasuringtherefractiv

10、eindexmodulationdepthandeffectivethicknessofphotorefractivevolumegratingispresented.BymeasuringtherelationshipoetweenQitrractioneftciencyandBraggangledeviationofvolumegratingtherefractiveindexmodulationdepthandefectiveth

11、icknessofphotorefractivevolumegratingcanbecalculatedaccordingtotheMBbandwidthrelativepeakvalueofsidelobeanditscorrespondingBraggangledeviationintherelationshipcurve.TheexperimentalresultswithLiNb03:Fecrystalarewellinagre

12、ementwiththetheoreticanalysis(4)Accordingtotherefractiveindexellipsoidofuniaxialbetweendiffractionefficiencyofvolumegratingandpolarizationtheoreticallyanalyzed.Thedirectionofrefractivelightbeamandcrystaltherelationshipst