简介:TheelectromagneticpropagationthroughaninhomogeneousmagnetizedplasmaslabisstudiedusingtheZ-transformformulationoftheFinite-DifferenceTime-Domain(FDTD)method.Thedirectionofelectromagneticpropagationisparalleltothebiasingmagneticfiled.TovalidatetheZ-transformalgorithm,thereflectionandtransmissioncoefficientsfortheright-handcircularlypolarizedwaveofthehomogeneousmagnetizedplasmaslabarecomputedbymeansofdiscreteFouriertransform.ThecomparisonbetweenthereflectionandtransmissioncoefficientsofthehomogeneousplasmaslabandanalyticalvaluesindicatesthatZ-transformalgorithmisveryaccurate.Whentheplasmafrequencyvariesaccordingtothesquarerootandparabolicrelations,thereflectionandtransmissioncoefficientsoftheinhomogeneousmagnetizedplasmaslabarecomputed.
简介:Anewmultiple-tapsandflatmicrowavephotonicfilter,whichiscomposedoffiberBragggrating,M-Zmodulatoranderbium-dopedfiber,isputforward.Theflatband-passorflatband-stopresponsecanberealizedbyadjustingthecoupler'sfactorandthereflectivityofthefiberBragggratingorthegainoftheerbium-dopedfiber.Thefreespectralrangeofthefiltercanbetunedbycontrollingthelengthoftheerbium-dopedfiber.Thepotentialandfeasibilityoftheproposedfilteringstructureshavebeendemonstratedbysimulation.
简介:OneoftheproblemsinusinggratingsensorsishowtomeasureasmallBraggwavelengthshiftaccurately.Nowadaysdemodulationtechniquesaremainlybasedontheedgefilter,tunablefilter,orinterferometricscanningmethods.Interferometricdemodulationiswidelyacceptedasthetechnologywhichcanprovidethehighsensitivity.Aninterrogationsystemusingtheinterferometricscanningmethodispresented,inwhichanunbalancedfiberM-Zinterferometerisusedasthewavelengthscannerfortemperaturemeasurement.AnovelfiberBragggratingsensorsystembasedonM-Zinterferometricdemodulationtechniqueispresentedinthispaper.Thetemperaturesensitivitymeasuredintheexperimentisalmostconsistentwiththatobtainedfromthetheoreticcalculation.
简介:Thispapergivesthestrictsolutionofopticalfieldequationintheopticalwaveguideswithparabolic.Itshowsthatthephotonsinthenon-uniformopti-calwaveguidepropagatealongz-axisinspiralform,justlikeachargedparticlesmovinginthemagneticfield.Onlyinthestep-indexwaveguides,itcanthephotonspropagateinzizagform.
简介:Theopticalparametersforthreesamplesofintrinsic,dopedSianddopedMg(AlxGa1-x)yIn1-yPpreparedbytheMOCVDonGaAssubstrateweremeasuredbyusingellipsometryandwerecalculatedbythetwo-layerabsorptionfilmmodel.Theresultsobtainedwerediscussed.Thegrownratesandthicknessofoxidiclayerontheintrinsic(AlxGa1-x)yIn1-yPsurfaceexposedintheatmospherewerestudied.Alineardependenceofoxidiclayerthicknessonthetimewasobtained.
简介:RamanscatteringspectroscopyisappliedtoinvestigatethephononmodesinGaxIn1-xP(x=0.52)and(AlxGa1-x)0.51In0.49P(x=0.29)alloys.Two-modebehaviorinGaxIn1-xPandthree-modebehaviorin(AlxGa1-x)0.51In0.49Pareobserved.InorderedGaxIn1-xP,weclearlydistinguishtheTO1(GaP-like)modeandthesplittingofLO1(GaP-like)andLO2(InP-like)modes,whichisbelievedtobetheresultofsuperlatticeeffectofordering,andtheLO1+LO2mode,whichisobservedforthefirsttime.Inadditiontotheb/aratio,it'sfoundthattherelativeintensityoftheFLAandtheLO1+LO2modesalsocorrespondstothedegreeoforder.TheTO1andthesplittingofLO1andLO2devotetogethertothereductionofthe'valleydepth'.In(AlxGa1-x)0.51In0.49P,thedoublingofFLAisobserved.DuetotheinfluenceofAlcomposition,theGaP-likeLOmodebecomesashoulderoftheInP-likeLOmode.TheunresolvedRamanspectraindicatetheexistenceoforderedstructurein(AlxGa1-x)0.51In0.49Palloys.
简介:Basedonthewhiteningpropertyofwavelettransformationfor1/fnoise,thispaperaddressestheproblemofdetectingdeterministicsignalsinthepresenceof1/ffractalnoise.Thetransferfunctionofwhiteningfilterisprovidedaswellastheconditionforwhitening.ThereceiverstructurebasedonKarhunen-Loeveexpansionandthedecisionrulearealsogiven.Finallyperformanceofthedetectorisanalyzed.