简介：Thetraditionalproportionalsolenoidhasdisadvantages,suchasbigsizeanddifficultyremoving.Sothispaperintroducesanewtypeofbi-directionalproportionalsolenoid,andexpoundsthestructureandworkingprincipleindetail.Onthisbasis,themathematicalmodeloftheproportionalsolenoidisestablished,anditsoutputcharacteristicisanalyzedbythefiniteelementtoolAnsoft/Maxwell.Itsstructureparameters'influenceontheoutputcharacteristicalsoisdiscussedthroughtheelectromagneticfieldanalysis.Thesimulationresultsshowthatthisnewtypeofbi-directionalproportionalsolenoidcanobtainagoodstaticcharacteristicwithoutthesamemagneticcircuitcontrolofthetraditionalproportionalsolenoid.

简介：Theintensityandpositionofthecouplingpointsinhighbirefringence(Hi-Bi)fiberscanbedetectedeffectivelyusingdistributedpolarizationcoupling(DPC)detection.Thedetectionsensitivitycandecreaseduetomechanicalvibrationdisturbanceandenvironmentnoise.Thus,amethodbasedonempiricalmodedecompositionisproposedtodetectweakmodecouplingpoints.Thesimulationandexperimentalresultsillustratethattheproposedmethodcansuppressthenoiseeffectivelyandimprovesensitivitysignificantly.Themethodcanidentifycouplingpointsasweakas-60dBembeddedinnoiseautomaticallyandeffectively.ThealgorithmisapplicableforDPC,andtheexperimentalsensitivityisimprovedby10dB.