简介：Weproposeanovelschemeforopticalfrequency-lockedmulti-carriergenerationbasedonadirectlymodulatedlaser(DML)andaphasemodulator(PM)incascadethroughsynchronoussinusoidalradiofrequency(RF)signal.TheoptimaloperatingzoneforthecascadedDMLandPMschemeisdeterminedviatheoreticalanalysisandnumericalsimulation.Wedemonstrate16opticalsubcarrierscanbesuccessfullygeneratedbasedonthecascadedDMLandPMschemeintheoptimalzone.Thegenerated16opticalsubcarrieshavefrequencyspacingof12.5GHzandpowerdi?erenceoflessthan3dB.Theseresultsagreewellwiththoseofthenumericalsimulation.Wealsodemonstrateintensitymodulationanddirectdetection(IM-DD)basedononeofthe16generatedopticalsubcarriers.After20-kmsingle-modefiber-28(SMF-28)transmission,thebit-errorratio(BER)of1×10-9canbeattainedforboth3.125-and12.5-Gb/sbitrates.

简介：Localizedmodesinone-dimensional(1D)mediawithuniaxialscatterersthatareassumedtobeorderinspatiallocationbutdisorderinspatialorientationoftheiropticalaxisareinvestigated.Basedontheholisticeffectmodelinrandomlaser,i.e.,therandomlaserisduetotheinteractionofthecomplexlocalizedmodesinactiverandommediawithlocalaperiodicquasi-structurewithappropriatepumplight,aphysicalmodelonthistypeofrandommediaisfound.ItsdisorderdegreeisdefinedbyD=n_o/n_e.Then,thetypicaltransmissionspectrumthroughtherandommediaandthelightfieldintensitydistributioncorrespondingtothedefectmodesinphotonicband-gaparecalculatednumericallybymeansofthetransfermatrixmethod,andtheconditionthatthelocalizedmodeappearsisdiscussed.Resultsshowthatthemediumdisorderplaysanimportantroleindeterminingthelightwavestate.Thelocalizedstateappearswhenthemediumdisorderisstrongenough,andanewmechanismcreatingrandomlaserphenomenonisbroughtforward.

简介：Theemergingperfect-absorbermetamaterials(PAMs)provideanalternativematerialapproachforthenextgenerationofelectromagneticdetectionatanyfrequencybandofinterest.Onetypeofdualcross-shapedPAMsisdevelopedtoobtainmultiplex-bandspectrumabsorptionatmid-infraredregion.Threedistinctabsorptionpeaksareattributedtothepolarizationsensitivityexcitationoftheplasmonicresonance.Thechargedensitydistributions,whichareexcitedbyresonantelectromagneticwavespassingthroughthePAMsmedium,provideinsightsintotheobservedabsorptionbehavior.WefindthattheretrievedopticalpropertiesofthePAMsincludingpermittivityandpermeabilityarestillconsistentwiththesumoftheDrudeandLorentztypemodelsatwavelengthsrangingfrom2.0to10.0mm.Suchmultiplex-bandabsorptionpropertiesenabletheproposedPAMsapowerfultoolforthedirectdetectionofmultiplemolecularvibrationalstructures,andformultiplespectrainfrareddetection.

简介：Thereisatradeoffbetweenthequantumefficiencyandthespectralresponselinewidthinresonant-cavityenhanced(RCE)photodetectors.Recentlyanewtypeofphotodetectorstructurehasbeenproposed,whichutilizesaninclinedmirrorinathree-mirrorcavity.Itdecouplesthequantumefficiencyandthespectralresponselinewidthandhashighresponsespeed,highquantumefficiency,andnarrowlinewidthsimultaneously.Theanalysisresultindicatesthatthelinewidthof0.8nmandquantumefficiencyhigherthan70%canbeachievedonthisdevice.Fora30×30μm2device,themaximumbandwidthapproaches23GHz.

简介：Thetransmissionpropertiesofone-dimensionalphotoniccrystalscontainingdouble-negativeandsingle-negativematerialsarestudiedtheoretically.Aspecialkindofphotonicbandgapisfoundinthisstructure.Thisgapisinvariantwithscalingandinsensitivetothicknessfluctuation.Butwhenchangingtheratioofthethicknessoftwomedia,thewidthofthegapcouldbeenlarged.Thedefectmodesareanalyzedbyinducingalineardefectlayerinthestructure.Itisfoundthatthenumberofdefectmodeswillincreasewhenthethicknessofthedefectlayerbecomeslarger.更多还原