简介:Anexperimentalwaytoanalyzethethermalcharacteriztionofsemiconductorlasersbasedonspectroscopymethodunderpulsedrivingconditionshasbeendeveloped,Byusingthiswaythethermalcharacteristicssofstraincompensated1.3μmInAsP/InGaAsPridgewaveguideMQWlaserdiodeshavebeeninvestigated.Resultsshovwthatbymeasuringandanalyzingthelasingspectraunderappropriatedrivingparametersandtemperatureranges,thethermalresistanceofthelaserdiodescouldbededucedeasily,Ahigerthermalresistanceof640K/Whasbeenmeasuredonanarrowridgelaserchipwithoutsoldering.Otherthermalandspectralpropertiesofthelaserhavealsobeenmeasuredanddiscussed.
简介:Recently,atunablefiberBragggrating(FBG)wasdevelopedbyusingstress-responsivecolloidalcrystals.Inthispaper,wehavesimulatedtheapplicationofthesenanoparticlesintothesuper-structuredfiberBragggrating(SSFBG)writtenwithperfectsequencesderivedfromashortmaximal-lengthsequence.AtunableSSFBGwillbeavailabletoovercometheprohibitivetemperaturevariationoftheopticalcodecs.Nevertheless,wepresentedamethodtoimplementcoherenttimespreadingopticalcode-divisionmultiple-access(OCDMA)whereauniquecode(orperfectsequence)canbereusedandmixedwithdifferentwavelengthstoobtainatunablewavelength-divisionmultiplexing(WDM)system.Inordertomaximizethebinarythroughput,wehaveselectedauniqueshortmaximal-lengthsequencecomposedof7chipsthatcanbetunedwith7differentopticalwavelengths.Wefoundthousandsofdifferenttunablecombinationsthatpresentedpowercontrastratios(P/C)higherthan12dB.WhenaWDM-OCDMAsystemused2differentcombinationssimultaneously,theperfectbinarydetectionwitherrorcorrectioncodeswasachievedsuccessfully.ThetunableSSFBGwithcolloidalcrystalswillbeasimpleandgoodalternativechoiceforfiber-to-the-home(FTTH)communications.
简介:Thetomographytechniqueiscommonlyusedforthereconstructionofholographicinterferometry.However,thecurrentreconstructionmethoddoesn'tconsiderthemeasurementerrorswhicharenon-avoidableinthemeasurementandwilldegradethereconstructionquality.Thefactorsaffectingthereconstructionqualityareanalyzedandthedistributionlawofthereconstructionerrorwithexperimentalerrorsisdiscussed.Finally,amethodtoimprovethereconstructionquality—theKalmanfiltermethodispresented.