光纤Bragg光栅传感.ppt

《光纤Bragg光栅传感.ppt》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、光纤Bragg光栅传感FiberBraggGratings國立中山大學電機工程研究所林武文教授2006.11.11Ref:AndreasOthonos&KyriacosKalli,FiberBraggGratings,ArtechHouse,Norwood,MA.U.S.A.199927.FiberBraggGratingSensors7.1Introduction7.2SensingExternalFields7.3WavelengthDemodulationofBraggGratingPointSensors7.4SimultaneousMeasurementofTem

2、peratureandStrain7.5PolarizationStabilityofInterrogationSchemes37.FiberBraggGratingSensors7.6MultiplexingTechniques7.7SensorsBasedonChirpedBraggGratings7.8DistinguishingBraggGratingStrainEffects7.9BraggGratingFiberLaserSensors7.10BraggGratingsasInterferometerSensorsandReflectiveMarkers41.1

3、FiberBraggGratings7.11OtherBraggSensorTypes7.12ApplicationsofBraggGratingSensors57.1IntroductionFBGissuitableformeasuring-Temperature-strain-pressure67.1IntroductionTheprincipaladvantageisthatthemeasuredinformationis-wavelengthencoded-flexibilitytonetwork-linearity(fromppb~%)-lowinsertionl

4、oss&narrowbandwavelength-reflection-easilyembeddedintomaterials77.1IntroductionThekeydetectionissueforFBGis-thedeterminationofsmallmeasurand-inducedwavelengthshifts.CategoryofFBGsensors-pointsensor-array(WDM/TDM/SDM)ordistributed-areflectivemarker(OTDR)-extremelylonggrating87.2SensingExter

5、nalFieldsInch.3welearned(1)Strainresponseofthegratingarisesfromthephysicalelongationofthesensor,leadingtoafractionalchangeinthegratingpitchwithacorrespondingchangeinthefiberindexbecauseofthephotoelasticeffect.97.2SensingExternalFields(2)Thermalresponse-inherentthermalexpansionofthefibermat

6、erial.-thetemperaturedependenceoftherefractiveindex.107.2SensingExternalFieldsEq(3.9)&(3.10)&(3.11)worksformeasuring-acceleration-ultrasonicwaves-forces117.2SensingExternalFields7.2.1PressureSensitivity7.2.2DynamicMagneticFieldSensitivity127.2.1PressureSensitivity(7.1)(7.2a)(7.2b)Apressure

7、changeofwavelengthshifForSMFWhereEisYoung’smodulus137.2.1PressureSensitivity(7.3a)(7.3b)(7.4)Given,thenormalizedpitchpressureisgivenbyFortherefractive-pressurecoefficientsaregivenbyTherefore147.2.2DynamicMagneticFieldSensitivity(DMFS)Faradayeffect-Alongitudina