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1、杭州电子科技大学硕士学位论文ABSTRACTDual-corephotoniccrystalfiberisanewtypeoftotalinternalreflectionphotoniccrystalfiber.Becauseofitsuniqueproperties,suchashighbirefringence,goodnonlinearityandsinglemodetransmission,ithasbeenwidelyusedinthefieldsofcurvature,temperature,pressure,torqueandspeedsensin
2、g.Inthispaper,thecoherentcharacteristicofDC-PCFisidentifiedandutilizedtodevelopanewtypeofopticalfiberlaserDopplervelocimetry(LDV)system.SinceDC-PCFhasastructurethattwotransmissioncoressharingacladdinglayer,theLVDsystemisgreatlysimplified.TheLDVsensingprobeisfurtherminiaturized,andisea
3、silyembeddedintoMEMSsystemtomeasurethevelocityofmicro/nanofluid.ThispaperdesignedanddevelopedtheLDVsystembasedonDC-PCF,including:(1)TransmissionandcoherencepropertiesofDC-PCF.Experimentalresultsshowedthatthefiberoutputoftwoindependentbeams,andbeamintensitycomplieswiththeGaussdistribut
4、ionandtheratioofintensityabout1:1.About30μmofthedistancetoopticalfiberendingfacet,thetwoindependentbeamsaresuperimposedtoform5interferencefringes.Asincreasingthedistancetoopticalfiberendingfacet,thespacingoftheinterferencefringesisgraduallyincreasing.Atthedistanceof2.0cm,theratioofthe
5、intensityofthesecondorderbrightstripewiththezeroorderandthefirstorderbrightstripeis1:2.4and1:3.4respectively.Butthecalculationresultsare1:4.5and1:3.5respectively.Obviously,thefringecontrastbasedonexperimentalhaslessthanthetheoreticalcalculation,resultingfromthenoiseduringtheexperiment
6、alprocess.(2)ProbemanufacturingingandsystemconfigurationofDC-PCF.Byusinghighvoltagedischargetechnology,theopticalfiberendisfusedtoproduceamicrolenThemicrolencanbeusedtooptimizethestructureoftheDC-PCF.Amultiparticleemissionsystemwasdesignedandfabricated,thelightscatteringcharacteristic
7、ofparticleswasanalyzed.TheLDVbasedonDC-PCFwasestablishedandimproved.(3)VelocitymeasurementbasedonDC-PCFLDV.AccordingtotheprinciplesofDC-PCFLDV,bycollectingtheforwardscatteringsignals,thesinglepoint,two-pointandthreepointvelocitymeasurementsarecarriedout.Forthesinglepointmeasurement,th
8、eaver
