简介：Asimplifiedmodalmethodtoexplaintheresonancephenomenoninguidedmoderesonance(GMR)gratingswithasymmetriccoatingsispresented.Theresonanceobservedisduetotheinteractionoftwopropagationmodesinsidethegrating.Thereflectivityspectraandelectricfielddistributionscalculatedfromthesimplifiedmodalmethodarecomparedusingrigorouscoupled-waveanalysis(RCWA).Theinfluencesofhigh-orderevanescentmodesontheresonancepeakareanalyzed.AmatrixFabry-Perot(FP)resonanceconditionisdevelopedtoevaluatetheresonancewavelength.AnexplanationfortheresonancephenomenonobservedbasedontheFPresonancephaseconditionisalsoproposedanddemonstrated.ThesimplifiedmethodprovidesclearphysicalinsightsintoGMRgratingsthatareusefulfortheanalysisofavarietyofotherresonancegratings.

简介：Weproposeahighsensitivitysensorbasedonamodenumber-encodedmulti-longitudinalmodefiberlaser.ThefiberlaserincorporatesauniformfiberBragggrating(FBG)andafiberFabry-Perotinterferometer(FFPI)assensitivecomponentsinthecavity.Thesensorcountsthenumberoflongitudinalmodes(NLM)offiberlaser,whichiscausedbythemismatchbetweenthereflectionbandofFBGandthetransmissionbandofFFPIresultingfromtheapplicationofexternalperturbationtotheFBG.AnelectricalspectrumanalyzerisadoptedtoanalyzetheNLM.Thestrainsensorisexperimentallydemonstratedtohavesensitivityofashighas0.02με/mode.

简介：Few-modefiberBragggrating(FM-FBG)haswideapplicationsinthefieldofmulti-wavelengthfiberlasersandfiber-opticsensing.Inthisletter,FBGissuccessfullywritteninanoveltypeofFMfiber(FMF)basedon248-nmexcimerlaserandauniformphasemask.Alow-losscouplingbetweentheFMFtoasinglemodefiberisrealizedbyagraded-indexmulti-modefiberwithalengthofaboutaquarterpitch.ThesensingpropertiesoftheFMFgratingarefurtherinvestigated.TheexperimentalresultsindicatethatthenovelFM-FBGhassensitivitiesoftemperature,strain,andbendingof11.2pm/C,1.3pm/με,and636.9pm/m1,respectively.

简介：ThisReviewfocusesonopticaltransmissionfibersandthehigh-capacitysystemsoperatingthereon.Itattemptstocombinekeylessonslearnedfromthe50-yearhistoryoflow-lossopticalfiberswithviewsonfuturefiberandsystemsrequirements,discussinglikelyevolutionpathsandpotentialpitfallsinresolvingtheopticalnetworkcapacitycrunch.

简介：Applicabilityofguidedmoderesonantstructurestotunableopticalfilteringandsensingisdemonstratedusingnematicliquidcrystals.Asasensor,aminimumrefractiveindexdetectivityof10-5isdemonstratedwhileasatunablefilter,tunabilityrangeoffewtensofnanometerswith2-nmbandwidthispresented.Theoptimumdesignisachievedbymaximizingtheevanescentfieldregionintheanalytewhichmaximizestheoverlapintegral.Thedevicecanbeoperatedinreflectionortransmissionmodesatnormalincidence.Itcanalsobeoperatedatasinglewavelengthbymeasuringtheangularprofileofthelightbeam.

简介：Awavelengthtunable,highrepetitionratemode-lockedfiberringlaserwasdemonstrated.Intheexperiment,photoniccrystalfiber(PCF)isusedasanintracavitycompressionmedium.ThehighnonlinearityandanomalousdispersionofPCFcancauseintracavitycompressionandresultinsignificantreductioninthepulsewidth.Thepulsesdurationattherepetitionrateof9.99GHzwaslessthan10psovertherangeof1532-1565nm.

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简介：Anopticalfibersensorforultrathinlayersensingbasedonshort-rangesurfaceplasmonpolariton(SRSPP)isproposed,andthesensingcharacteristicsaretheoreticallyanalyzed.Simulationresultsindicatethatevenforadetectinglayermuchthinnerthanthevacuumwavelength,aresolutionashighas3.7×10-6RIUcanbeobtained.Moreover,anaveragethickness-detectionsensitivityof6.2dB/nmisobtained,whichenablesthesensortodetectthethicknessvariationoftheultrathinlayeruptotensofnanometers.Thesensitiveregionofthicknesscouldbeadjustedbytuningthestructureparameters.

简介：Hybridoctagonal-ringmicrolasersareinvestigatedforrealizingastableoutputfromasiliconwaveguidebasedonatwo-dimensionalsimulation.Theinnerradiusoftheringisoptimizedtoachievesingle-modeandlow-thresholdoperation.Usingthedivinylsiloxane-benzocyclobutene(DVS-BCB)bondingtechnique,ahybridAlGaInAs/Sioctagonal-ringmicrolaserverticallycoupledtoasiliconwaveguideisfabricatedwithasidelengthof21.6μmandaninnerradiusof15μm.Asingletransverse-modeoperationisachievedwithathresholdcurrentdensityof0.8kA∕cm~2andaside-modesuppressionratioabove30dB,andastableoutputfromthelowersiliconwaveguideisobtained.

简介：Aterahertzexcitationsourcebasedonadual-lateral-modedistributedBraggreflector(DBR)laserworkinginthe1.5μmrangeisexperimentallydemonstrated.Byoptimizingthewidthoftheridgewaveguide,thefundamentalandthefirst-orderlateralmodesareobtainedfromthelaser.Themodespacingbetweenthetwomodesis9.68nm,correspondingtoabeatsignalof1.21THz.BytuningthebiascurrentsofthephaseandDBRsections,thewavelengthsofthetwomodescanbetunedby2nm,withasmallstrengthdifference(<5dB)andalargeside-modesuppressionratio(SMSR>45dB).

简介：Wepresentatabletop-scalespotlight-modedown-lookingsyntheticapertureimagingladar(DLSAIL)demonstrator,whichisperformedbyacollimatorwith10mfocallengthtosimulatethefar-fieldopticalfield.Aspecular-pointtargetandadiffuse-reflectiontargethavebeenusedforresolutionanalysisand2Dimaging,respectively.Theexperimentalresultisinagreementwiththetheoreticaldesign.Theexperimentsetupiscapableofsimulatingarealapplicationscenarioforfurtherstudy.ThisLetterisfocusedonthepropositionandimplementationofspotlight-modeDLSAIL.

简介：Anopticallyactivatedopticalswitchbasedonsuppressionofmodeinterference(SMI)ispresented.Theimagingpropertiesofmulti-modeinterference(MMI)sectionintheswitchwithY-branchcanbemodifiedbyacontrollinglightinjection.Theswitchwassimulatedbyfinitedifferencebeampropagationmethod(FD-BPM)andfabricatedonGaAlAs/GaAsepitaxialmaterials.Atthewavelengthof1.31μm,theprimaryexperimentshowedanextinctionratioofabout8dBwithcontrollinglightpowerdensityof73.5W/mm2.

简介：WecreateaGaNphotocathodebasedongradedAlxGa1-xNbufferlayerstoovercometheinfluenceofbuffer-emissionlayerinterfaceonthephotoemissionoftransmission-modeGaNphotocathodes.Agateshapedspectralresponsewitha260-nmstartingwavelengthanda375-nmcut-offwavelengthisobtained.Averagequantumefficiencyis15%andshortwavelengthresponsesarealmostequivalenttolongwavelengthones.Thefittedinterfacerecombinationvelocityis5×104cm/s,withnegligiblemagnitude,provingthatthedesignofthegradedbufferlayersisefficientinobtaininggoodinterfacequalitybetweenthebufferandtheemissionlayer.

简介：Thenumericalstudyontheperformanceoflarge-mode-area(LMA)fiberscoiledontoaspoolinhighpoweramplifieriscarriedoutasthebend-induceddistortionoffibermodesseverelyaffectstheoutputcharacteristicsofamplifiersystems.Thevariationsforhigh-ordermodebenddistortionwithdifferentorientationsrelativetotheplaneofthefiberbendareobservedandshown.Concerningthepracticalapplications,abend-resistantLMAfiberwiththemodearealargerthan1000μm2andexcellenthighordermodesuppressionisdesignedcompletelybyoptimizingtherefractiveindex(RI)anddopantprofile.TheresultsindicatethatahybridprofileofRIanddopantisthebestchoiceforLMAfiberwithcoiling.

简介：Acoupleofsimple-structurephasemodulatorswereusedinactivemode-lockedfiberlasertoimplementrepetitionratecontinuoustuning.Thelaserproducespulseasshortas5.7pswhoserepetitionratetuningcancoverthespacingoftheadjoiningordermode-lockingfrequencies.

简介：Consideringasingle-modelasersystemwithcross-correlatedadditivecolorednoiseandmultiplicativecolorednoise,westudytheeffectsofcorrelationamongnoisesonthenormalizedintensitycorrelationfunctionC(s).C(s)isderivedbymeansoftheprojectionoperatormethod.Theeffectsoftheself-correlationtimeτ_1oftheadditivecolorednoise,τ_2ofthemultiplicativecolorednoise,andtheeffectofthecross-correlationtimeτ_0betweenthetwonoisesonC(s)arediscussedbynumericalcalculation.Forthecaseofpositivecorrelation(λ>0),itisfoundthatwhena_0>0thenormalizedintensitycorrelationfunctionC(s)increaseswiththeincreaseofToorτ_2,andwithvalueofτ_0orτ_2becominglarger,C(s)comestosaturation.Withincreasingtheself-correlationtimeτ_1oftheadditivenoise,aminimumandamaximumwillappearoncurveofC(s)asa_0>0.Ifa_0<0,C(s)decreaseswiththeincreaseofτ_0,τ_1,andτ_2.

简介：Anoptimizeddesignoflaserrangefindingsystemusingtheself-mixingeffectinasingle-modevertical-cavitysurface-emittinglaser(VCSEL)isproposed.Inordertoimprovetherangingaccuracyandexpanddynamicmeasurementrange,weapplydifferencefrequencyanalogphase-lockedloop(PLL)insteadoffastFouriertransform(FFT)toprocesssignal,andchoosetheoptimumtriangularwavefrequencyfm=500Hzandsmallmodulationcurrent△Ip-p=0.28mAtomodulatesingle-modeVCSEL.Theexperimentresultsshowthat,withoutcontrollingthelaser'stemperature,therangingaccuracyisbetterthan2mmandthemeasurementdynamicrangeisaslargeas50-500mmwhenthesamplingtimeis0,1sandtheroomtemperatureis0-55℃.

简介：Weexperimentallydemonstrateall-opticalclockrecoveryfor100Gb/sreturn-to-zeroon–offkeyingsignalsbasedonamonolithicdual-modedistributedBraggreflector(DBR)laser,whichcanrealizebothmodespacingandwavelengthtuning.Byusingacoherentinjectionlockingscheme,a100GHzopticalclockcanberecoveredwithatimingjitterof530fs,whichisderivedbyanopticalsamplingoscilloscopefromboththephasenoiseandthepowerfluctuation.Furthermore,fordegradedinjectionsignalswithanopticalsignal-to-noiseratioaslowas4.1dBanda25kmlongdistancetransmission,good-qualityopticalclocksareallsuccessfullyrecovered.

简介：AhighlyTm-dopedleadgermanateglassfiberisdevelopedusingtherod-in-tubemethod.The~2μmlaserbeamqualityofthefiberis~1.5.Theleadgermanatecompositefiberjumpersarehomemadeforallthefiberlaserinvestigations.Whencoreispumpedbya1590nmYb/Erfiberlaser,amaximumlaseroutputof313mWisachievedata670mWpumppower,andthecorrespondingslopeefficiencyis~52.8%.Moreover,byusinga2cmlongleadgermanatefiberasthegainmedium,a33mW1942nmTmlaserisalsodemonstrated.

简介：Wereportontheamplificationofhigh-average-powerandhigh-efficiencypicosecondpulsesinaself-madeverylarge-mode-areaYb-dopedphotoniccrystalfiber(PCF).ThePCFwithacorediameterof105μmandacorenumericalapertureof0.05ispreparedbythesol-gelmethodcombinedwiththepowdersinteringtechnique.Thefiberamplificationsystemproducesthehighestaveragepowerof255Wata10MHzrepetitionratewitha21pspulsedurationcorrespondingtoapeakpowerof1.2MW.Thisresultexemplifiesthehigh-average-powerandhigh-peak-powerpotentialofthisspecificallydesignedfiber.