简介：Weexperimentallydemonstratea4-Gb/sradio-over-fiber(RoF)systemwith40-kmfiberand2-mwirelessdistancedownstreamat100-GHzcarrier.Tothebestofourknowledge,thisisforthefirsttimeinChinatorealizeopticalwirelesslinkat100GHz.Inthisletter,simpleintensitymodulatorwithdirectdetector(IM-DD)modulationisemployedandopticalpowerpenaltyafter40-kmsinglemodefiber(SMF)-28and2-mairlinkis3.2dBwithbit-error-rate(BER)at1×109.

简介：Theauthorsregretthatoneofthecoauthorswasinadvertentlyomittedinthepreviouspaper[1].E.VarenewasamemberoftheInstitutfrFestkrperphysikattheTechnischeUniversittBerlinandcontributedtotheresultsoncross-phasemodulation.

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：宽波段红外成像技术可以获取丰富的波段信息,在目标识别和频谱分析中具有独特的优势。设计了一种1.3-5μm宽波段短中波红外光学系统,该光学系统采用二次成像设计,包括7块透镜和2片反射镜,其中使用了2片硅非球面和1片硒化锌基底衍射面用以校正像差和色差。利用光学设计软件给出了系统的光学参数和二维外形结构图,并且对其像质和冷反射进行了系统分析。该系统可以实现在工作波段1.3-5μm宽波段中成像,其F数为2,满足100%冷光阑效率。该系统结构紧凑,像质较好,能够实现宽波段成像要求。

简介：Inthispaper,wederivethebrightanddarkphotonnumberstatesforspatialinterferenceoftwoormorelightbeamsandsucceedintheexplanationofYoung'sinterferenceexperiment,andalsoachieveabettercomprehensionofthewellknowncommentofDirac"eachphotononlyinterferenceswithitself".Fromthefullyquantumpointofview,theoriginoftheinterferencefringesconsistsinthemodetransformationandthedetectionofdouble-slitstates.

简介：A1.3-μmwavelengthvertical-mesaridgewaveguidemulitple-quantum-well(MQW)distributedfeedback(DFB)laserwithhighdirectlymodulatedbandwidthandwideoperationtemperaturerangeisreported.Withtheoptimizationofthestrained-layerMQWsintheactiveregion,thesurroundinggraded-indexseparated-confinement-heterostructurewaveguidelayers,togetherwiththeoptimizationofthedetuningandcouplingcoefficientoftheDFBgrating,highdirectlymodulationbandwidthof16GHzatroomtemperatureandwideworkingtemperaturerangefrom-40to85℃areobtained.Themeantimetofailure(MTTF)isestimatedtobeover2×10~6h.Thedeviceissuitableaslightsourceofhigh-bit-rateopticaltransmitterswithsmallsizeandreducedcost.

简介：Diode-pumpedpassivelyQ-switchedNd:GdVO4/Cr4+:YAGlaserswithasimpleflat-flatcavityweredemonstrated.Themaximumaverageoutputpowerat1.06μmwas1.25W.Thehighestpeakpowerandpulseenergywere7.56kWand75μJ,respectively,withthepulserepetitionrateof11.1kHzandpulsewidthof10nsattheincidentpumppowerof8W.

简介：Thecavitytuningcharacteristicsoforthogonallypolarizeddual-frequencyHe-Nelaserat1.15μmarepresented.Vectorial-extensionmodelbasedonsemi-classicallasertheoryrevealsthatcavitytuningcharacteristicsarerelatedtobeatfrequency,relativeexcitation,andtypeofNeisotope.Distortionsofcavitytuningcurvesbecomemoderatewiththeincreaseofbeatfrequencybecauseoftheweakeningofthecrosssaturationeffect.Distortionsareenhancedwiththeincreaseofrelativeexcitationbecauseofthecombinedactionoftheself-saturationandcross-saturationeffects.Byadoptingdual-isotopeNeinsteadofmonoiso-toplicNe,distortionsarereducedbecauseofthemisalignmentbetweenpeaksoftheself-saturationandnetgaincoefficients.Thetheoreticalcalculationsareingoodagreementwiththecorrespondingexperimentalresults.

简介：Asecondgenerationsolaradaptiveoptics(AO)systemisbuiltandinstalledatthe1-mNewVacuumSolarTelescope(NVST)oftheFuxianSolarObservatory(FSO)in2015.TheAOhigh-ordercorrectionsystemconsistsofa151-elementdeformablemirror(DM),acorrelatingShack–Hartmann(SH)wavefrontsensor(WFS)witha3500Hzframerate,andareal-timecontroller.ThesystemsawfirstlightonMar.16,2015.Thesimultaneoushigh-resolutionphotosphereandchromosphereimageswithAOareobtained.Theon-skyobservationalresultsshowthatthecontrastandresolutionoftheimagesareapparentlyimprovedafterthewavefrontcorrectionbyAO.

简介：Aperiodicallypoledlithiumniobate(PPLN)opticalparametricgenerator(OPG)pumpedbyalaserdiode(LD)-pumpedQ-switchedTm,Ho:GdVO_4laseroperatedat2.048μmwithpumppulseof25nsandrepetitionrateof10kHzisreported.Acontinuoustunablemiddle-infrared(mid-IR)spectrumof3.88-4.34μmisobtainedbychangingthecrystaltemperaturefrom50to124°C.Whentheincidentpumppoweris3W,thetotalOPGoutputpoweris95mW,correspondingtoopticalconversionefficiencyof3.2%.

简介：Anexperimentofadaptivepolarizationmodedispersion(PMD)compensationfor40-Gb/sreturn-to-zero(RZ)opticalcommunicationsystemisreported.Intheexperiment,degreeofpolarization(DOP)isusedasfeedbacksignalandparticleswarmoptimization(PSO)methodisadoptedaslogiccontrolalgorithm.Thecompensationtimeisabout200ms,thecompensateddifferentialgroupdelay(DGD)isupto30ps,andbiterrorrate(BER)of10^-9isreachedwhenPMDcompensationisemployed.

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

简介：Anewscreen-spotimagingmethodbasedonopticalmeasurementisproposed,whichisapplicabletotheclose-rangemeasurementofaircraft'sthree-dimensional(3D)attitudeparameters.Lasertrackerisusedtofinishtheglobalcalibrationsofthehigh-speedcamerasandthefixedscreensontestsite,aswellastoestablishmedia-coordinate-framesamongvariouscoordinatesystems.Thelasercooperationobjectmountedontheaircraftsurfaceprojectslaserbeamsonthescreensandthehigh-speedcamerassyn-chronouslyrecordthelight-spots'positionchangingwithaircraftattitude.Therecordedimagesequencesareusedtocomputetheaircraftattitudeparameters.Basedonthematrixanalysis,theerrorsourcesofthemeasurementaccuracyareanalyzed,andthemaximumrelativeerrorofthismathematicalmodelisestimated.Theexperimentalresultshowsthatthismethodeffectivelymakesthechangeofaircraftpositiondistinguishable,andtheerrorofthismethodisnomorethan3′whiletherotationanglesofthreeaxesarewithinacertainrange.

简介：WhenfemtosecondlaserpulsesinterferewithchirpedfemtosecondlaserpulsesinAs2S3fiber,achirpedfibergratingisformed.Ananalyticalexpressionisgiventodescribethechirpedgrating,anditsBraggreflectivityiscalculated.BecauseofthehighphotosensitiveeffectofAs2S3material,thechirpedfibergratinghasawideBraggreflectivespectrumandhighreflectivitybychoosingproperparameters.Thisindicatesthatthechirpedfibergratingcanbeusedasastretcherinthefemtosecondchirpedpulseamplification(CPA)system.

简介：ByusingPDM-OFDM-16QAMmodulation,all-Ramanamplification,coherentdetection,and7%forwarderrorcorrection(FEC)threshold,wesuccessfullydemonstrate63-Tb/s(368×183.3-Gb/s)signalover160-kmstandardsinglemodefiber(SSMF)transmissionintheC-andL-bandswith25-GHzchannelspacing.368opticalchannelswithbandwidthspacingof25GHzaregeneratedfrom16externalcavitylasersources.After160-kmSSMFtransmission,alltestedbiterrorrate(BER)areunder3.8×10-3,whichcanberecoveredby7%FECthreshold.Withineachchannel,weachievethespectralefficiencyof6.85bit/s/HzinC/Lband.

简介：使用傅里叶变换光谱仪（FTIR）测试甚长波宽波段（6．4～15μm）红外探测器响应光谱的过程中，发现短波方向响应光谱异常。通过分步测试分析发现：探测器和放大器工作在非线性工作区导致某些情况下仪器信号发生饱和，引起了短波方向响应光谱畸变的现象。对FTIR测量甚长波宽波段（6．4～15μm）红外探测器响应光谱的畸变现象进行了分析，认为探测器的响应时间是影响其响应光谱的重要因素，并通过试验确定了测试系统对不同探测器所设置的测试参数，消除了响应光谱畸变的现象，并提高了测试准确度。

简介：

简介：我们求婚并且试验性地证明为M照振幅调整(正交调幅)追踪计划的一个通用、盲目的极化状态基于一个没有决定的指导半径的线性Kalman过滤器(RD-LKF)发信号。追踪性能的极化为调音的照阶段移动(QPSK)和16正交调幅信号通过模拟和实验被调查。静态的极化demultiplexing性能和动态追踪能力上的过滤器参数的影响经由模拟被讨论。在modulation-format-independent情形的过滤器参数的优化策略被建议，模拟被执行为QPSK，16QAM，和混合QPSK/16QAM信号评估极化demultiplexing惩罚。最后，建议没有决定的RD-LKF是试验性地，与经常的模量算法的各自的算法和为QPSK和16正交调幅和ultrafast极化追踪的优点的multimodulus算法相比，能力被证实。

简介：Ahigh-repetition-rateeye-safeopticalparametricoscillator(OPO),usinganon-criticallyphase-matchedKTPcrystalintracavitypumpedbyapassivelyQ-switchedNd:GdVO_4/Cr~(4+):YAGlaser,isexperimentallydemonstrated.Theconversionefficiencyfortheaveragepoweris7%frompumpdiodeinputtoOPOsignaloutputandtheslopeefficiencyisupto10.3%.Withanincidentpumppowerof7.3W,thecompactintracavityOPO(IOPO)cavity,operatingat15kHz,producesanaveragepowerof0.57Wat1570nmwithapulsewidthasshortas6ns.Thepeakpowerat1570nmishigherthan6.3kW.

简介：Aquasi-cycliclow-densityparitycheck(QC-LDPC)codeisconstructedbyanimp