A distributed optical fiber sensing system for synchronous vibration and loss measurement

(整期优先)网络出版时间:2016-05-15
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Weproposeafullydistributedfusionsystemcombiningphase-sensitiveopticaltime-domainreflectometry(Φ-OTDR)andOTDRforsynchronousvibrationandlossmeasurementbysettinganingeniousfrequencysweeprate(FSR)oftheopticalsource.TherelationshipsbetweenFSR,probepulsewidthandrepeatperiodaregiventobalancetheamplitudefluctuationofOTDRtraces,thedeadzoneprobabilityandthemeasurablefrequencyrangeofvibrationevents.Intheexperiment,weachievesynchronousvibrationandlossmeasurementwithFSRof40MHz/s,theproblepulsewidthof100nsandrepeatrateof0.4ms.ThefluctuationofOTDRtraceislessthan0.45dBwhenthesignalto-noiseratio(SNR)isover12dBforacapturedvibrationeventlocatedat9.1km.Theproposedmethodcanbeusedfornotonlydetectionbutalsoearlywarningofdamageeventsinopticalcommunicationnetworks.