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

  • 标签: 分布布拉格反射 太赫兹 激光器 双模式 激发 波长可调谐
  • 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。

  • 标签: 光学设计 红外成像 宽波段 衍射 冷反射
  • 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.

  • 标签: DFB激光器 工作温度范围 脊波导 平均无故障时间 非制冷 分布式反馈
  • 简介:Themicrowavephotonicfilters(MPFs)basedonseriallycoupledsiliconmicroringresonators(MRRs)aretheoreticallyanalyzedfortheapplicationof60-GHzmillimeterwavewirelesspersonalareanetworks.Thisisachievedbycalculatingtheimprovementofbiterrorratio(BER).Accordingtothesimulationresults,therequirementofsignal-to-noiseratio(SNR)ofthereceiveddatacanbereducedby14dBforthesameBERwithandwithoutMPFs.TheperformanceoftheMPFwithfiveseriallycoupledmicroringstructuresisbetterthanthatoftheMPFwithasinglemicroring,owingtotheimprovementoftheshapefactor.

  • 标签: 微波光子 谐振器 滤波器 GHZ 微环 串行
  • 简介:Diode-pumpedpassivelyQ-switchedNd:GdVO4/Cr4+:YAGlaserswithasimpleflat-flatcavityweredemonstrated.Themaximumaverageoutputpowerat1.06μmwas1.25W.Thehighestpeakpowerandpulseenergywere7.56kWand75μJ,respectively,withthepulserepetitionrateof11.1kHzandpulsewidthof10nsattheincidentpumppowerof8W.

  • 标签: 调Q激光器 铌掺杂 钒酸钆晶体 ND:GDVO4 二极管泵浦
  • 简介:Thecavitytuningcharacteristicsoforthogonallypolarizeddual-frequencyHe-Nelaserat1.15μmarepresented.Vectorial-extensionmodelbasedonsemi-classicallasertheoryrevealsthatcavitytuningcharacteristicsarerelatedtobeatfrequency,relativeexcitation,andtypeofNeisotope.Distortionsofcavitytuningcurvesbecomemoderatewiththeincreaseofbeatfrequencybecauseoftheweakeningofthecrosssaturationeffect.Distortionsareenhancedwiththeincreaseofrelativeexcitationbecauseofthecombinedactionoftheself-saturationandcross-saturationeffects.Byadoptingdual-isotopeNeinsteadofmonoiso-toplicNe,distortionsarereducedbecauseofthemisalignmentbetweenpeaksoftheself-saturationandnetgaincoefficients.Thetheoreticalcalculationsareingoodagreementwiththecorrespondingexperimentalresults.

  • 标签: 调谐特性 正交偏振 HE-NE激光 双频 微米 氖同位素
  • 简介:Aweakinfrared(IR)imageamplifierwithmorethan60-dBopticalgainandfrequencyup-conversionisdevelopedfromapicosecond(PS)355-nmpumpedgatedopticalparametricamplifier(OPA)inaβ-BaB2O4(BBO)crystal.TheIRimageat1064nmisamplifiedandup-convertedintothevisibleregionat532nmbyparametricamplificationandup-conversion.Withtheoptimizedopticalgain,thelowestdetectableenergyoftheimagecanbeaslowas1.8femto-Jouleperpulse,whichisthreeordersofmagnitudelowerthanthedetectionlimitofacharge-coupleddevice(CCD)camera.ThetransversalresolutionoftheOPAimagingisinvestigated,andtheapproachesforhigherdetectionsensitivityandhighertransversalresolutionareproposed.

  • 标签: 频率上转换 放大器 光增益 光学参量 成像 皮秒
  • 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.

  • 标签: 自适应光学系统 太阳望远镜 天文台 抚仙湖 第二代 真空
  • 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%.

  • 标签: 周期性极点 波长 转化率 光学参数 发电机
  • 简介:AhighlyTm-dopedleadgermanateglassfiberisdevelopedusingtherod-in-tubemethod.The~2μmlaserbeamqualityofthefiberis~1.5.Theleadgermanatecompositefiberjumpersarehomemadeforallthefiberlaserinvestigations.Whencoreispumpedbya1590nmYb/Erfiberlaser,amaximumlaseroutputof313mWisachievedata670mWpumppower,andthecorrespondingslopeefficiencyis~52.8%.Moreover,byusinga2cmlongleadgermanatefiberasthegainmedium,a33mW1942nmTmlaserisalsodemonstrated.

  • 标签: 激光光束质量 复合纤维 锗酸盐 TM 掺杂 光纤激光器
  • 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。

  • 标签: 傅里叶变换光谱仪 甚长波宽波段红外探测器 探测器饱和 响应光谱 响应时间
  • 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。

  • 标签: KALMAN滤波器 QAM信号 解复用 M-QAM 偏振 自由
  • 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.

  • 标签: ND:GDVO4 光学参数 震荡器 波长
  • 简介:在采用图像检测技术对轴套类零尺寸进行高精度检测中,提出了一种高精度零尺寸图像检测方法,在获取零图像后,采用Prewitt算子完成对图像边缘的初步定位,在此基础上,通过对图像边缘灰度变化的离散值作最小二乘曲线拟合,并对该拟合曲线求极值,得到边缘位置;为了减少干扰对测量值的影响,采用误差数据处理方法筛选出有一定精度的检测数据,然后对这些检测数据求平均值,获得精确的边缘位置,由此计算出精确的零尺寸。实验表明,该方法能有效地提高检测精度,在检测分辨率为1000DPI情况下,检测精度可达到13μm

  • 标签: 光电检测 图像检测 边缘 最小二乘曲线拟合 误差理论
  • 简介:Enhanced2.7μmemissionisobtainedinEr3+/Tm3+andEr3+/Ho3+codopedZBYAglasses.Absorptionandemissionspectraaretestedtocharacterizethe2.7μmemissionpropertiesofEr3+/Tm3+andEr3+/Ho3+dopedZBYAglassesandareasonableenergytransfermechanismof2.7μmemissionbetweenEr3+andTm3+Ho3+)ionisproposed.CodopingofTm3+orHo3+significantlyreducesthelifetimeoftheEr3+:4I13/2levelduetotheenergytransferofEr3+:4I13/2→Tm3+:3F4orEr3+:4I13/2→Ho3+:5I7.Thus,the2.7μmemissionisstrengthenedandthe1.5μmemissionisdecreasedaccordinglyespeciallyintheEr3+/Tm3+sample.TheupconversioneffectsbetweentheEr3+/Tm3+andEr3+/Ho3+dopedZBYAglassesaredifferentattributetothedifferentenergytransferefficiencies.Bothofthetwocodopedsamplespossessnearlyequallargeemissioncrosssection(16.6×10-21cm-2)around2.7μm.TheresultsindicatethatthisEr3+/Tm3+orEr3+/Ho3+dopedZBYAglasshaspotentialapplicationsin2.7μmlaser.

  • 标签: 能量转移效率 能量传递机制 氟化物玻璃 发射光谱 共掺杂
  • 简介:Real-timevideostreamingusingultra-wideband(UWB)technologyisexperimentallydemonstratedalonglong-reachpassiveopticalnetworks(LR-PONs)withdifferentwiredandwirelessreaches.ExperimentaltestsusingexternalanddirectmodulationwithUWBwirelessradiationinthe10-and60-GHzbandsareperformed.Anultra-bendablefiberisalsoconsideredforalast-miledistribution.ThevideoqualityattheoutputoftheopticalfiberinfrastructureoftheLR-PONisassessedusingtheerrorvectormagnitude(EVM),andthelinkqualityindicator(LQI)isusedasafigureofmeritafterwirelessradiation.AnEVMbelow–17dBisachievedforbothexternallyanddirectlymodulatedLR-PONscomprisingupto125kmofopticalfiber.EVMimprovementisobservedforlongerLR-PONswhendirectlymodulatedlasers(DMLs)areusedbecauseoftheamplitudegainprovidedbythecombinedeffectofdispersionandDML’schirp.Comparedwithopticalback-to-backoperation,theLQIleveldegradestothemaximumaround20%forLR-PONsrangingbetween75and125kmoffiberreachandwithawirelesscoverageof2minthe10-GHzUWBband.ThesamelevelofLQIdegradationisobservedusingthe60-GHzUWBbandwithaLR-PONintegrating101kmofaccessnetwork,alast-miledistributionusingultra-bendablefiber,anda5.2-mwirelesslink.

  • 标签:
  • 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.

  • 标签: 无线传输 单模光纤 试验示范 载波 OOK 强度调制器