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1、重庆大学硕士学位论文长距离布拉格光纤光栅传感系统研究姓名:陈容睿申请学位级别:硕士专业:光学工程指导教师:饶云江20060501重庆大学硕士论文ABSTRACTWiththerapiddevelopmentoflargecompositeandconcreteinfrastructuresinChina,moreadvancedsensingsystemsareneededintheconstructionandmonitoringofimportantprojects.FiberBraggGrating(FBG)isideallysuited
2、forreal-timestructuralhealthmonitoringofoilpipelineanddametcbecauseofitsuniquecharacteristic.FBGcanbeeasilyembeddedorattachedtothestructures,andFBGsensorarraysareeasilymadefortemperatureandstrainmonitoringbyconnectingseveralBragggratingswrittenatdifferentwavelengthseriallyin
3、alinealongasinglefiber.Thesensingtransmissiondistancewithabroadbandlightsourceislimitedupto25kmmainlyduetotransmissionlossofopticfiber,Rayleighscatteringandintrinsiclossofthefiberlink.Thepurposeofthisthesisistostudynovelmethodstorealizelong-distanceandremotesensingwithlowcos
4、tandgoodpracticability.Themainpointsofthethesisareasfollows:Firstly,theprinciplesandapplicationofFBGsensorareanalyzed,andtheexistingmethodsoflongdistanceFBGsensingsystemareinvestigatedandcompared.Opticamplificationtechnologyisanalyzedandcompared,andthenEDFAandFRAarechosentoa
5、pplytothelongdistancesensingsystem.Secondly,adrivingcircuitofpumplaserisdesignedandmanufactured,whichisbasedonAtmel89C52MCU,andperipheralcircuitsofthesystemareaccomplishedincludingA/D,D/A,EEPROM,LCD,pumpprotection,temperaturecontrolling,signalconditioning,etc.Thecircuitisapp
6、liedtoEDFAandFRAinthesensingsystem.Thirdly,anovelmethodoflongdistancesensingsystembasedonEDFA/FRAhybridamplificationisproposed.AbroadbandsourceisusedtoprovidereflectivelightforFBG.Thesensingdistanceisupto50kmandtheSNRofsensingsignalis14dB.Then,afiberringlasersourceisusedforr
7、eplacingthebroadbandsource,atunablefilterisusedtodifferentiatesensingsignals,theexcellentSNRof58dBisachievedalong50kmopticfiber.Finally,thestability,multiplexing,temperaturesensing,staticanddynamicstrainsensingexperimentsarecarriedoutwithsensingsystembasedonafiberringlaser.T
8、heresultsshowthatthesystemworkswell.Thereisgoodlinearitybetweenthewavelengt