简介:AnovelopticalfibersensorwithaU-shapedmicro-groovestructureablatedbyfemtosecondlaseronsingle-modefi-berformeasuringairrelativehumidity(RH)isreportedinthispaper.Inordertoimprovetheaccuracyofsensor,agrapheneoxide(GO)/polyvinylalcohol(PVA)compositefilmiscoatedonthesurfaceofmicro-groovestructure.IntheU-shapedmicro-groovestructure,theremainingcoreandmicro-cavityinthemicro-groovemakeuptwomajorop-ticalpropagationpaths,formingaMach-Zehnderinterferometer(MZI).ThesensorhasagoodlinearresponsewithintheRHrangeof30%--85%,andthemaximumsensitivitycanreach0.6381mrd%RH.Theeffectoftemperatureontheoverallperformanceofthehumiditysensorisalsoinvestigated.Asanewtypeofall-fiberdevice,thesensorshowsexcellentsensitivityandstability.