学科分类
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13 个结果
  • 简介:Inthispaper,wederivethebrightanddarkphotonnumberstatesforspatialinterferenceoftwoormorelightbeamsandsucceedintheexplanationofYoung'sinterferenceexperiment,andalsoachieveabettercomprehensionofthewellknowncommentofDirac"eachphotononlyinterferenceswithitself".Fromthefullyquantumpointofview,theoriginoftheinterferencefringesconsistsinthemodetransformationandthedetectionofdouble-slitstates.

  • 标签: 信息光学 亮光子数态 暗光子数态 相干实验
  • 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.

  • 标签: 光学通信系统 偏振散射模式补偿 粒子群优化理论 逻辑控制运算器 补偿时间
  • 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.

  • 标签: 光学测量 航行器 三维姿态估计 精确性估计
  • 简介:WhenfemtosecondlaserpulsesinterferewithchirpedfemtosecondlaserpulsesinAs2S3fiber,achirpedfibergratingisformed.Ananalyticalexpressionisgiventodescribethechirpedgrating,anditsBraggreflectivityiscalculated.BecauseofthehighphotosensitiveeffectofAs2S3material,thechirpedfibergratinghasawideBraggreflectivespectrumandhighreflectivitybychoosingproperparameters.Thisindicatesthatthechirpedfibergratingcanbeusedasastretcherinthefemtosecondchirpedpulseamplification(CPA)system.

  • 标签: As2S3 三硫化二砷 啁啾光纤光栅 双光子吸收效应 飞秒啁啾脉冲放大器 CPA
  • 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.

  • 标签: 16QAM调制 拉曼放大 L波段 C波段 公里 传输
  • 简介:Aquasi-cycliclow-densityparitycheck(QC-LDPC)codeisconstructedbyanimp

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

  • 标签: DBR激光器 光时钟恢复 双模 单片 分布布拉格反射 光学信号
  • 简介:Anovelmethodfordistortion-freeopticalpulsetransmissionistheoreticallyproposedandsimulated,inwhichtwotimelensesformedbydispersionfibersandquadraticphasemodulationsareutilized.OneisusedasanopticalinverseFouriertransformation(OIFT)devicetotransformtheinitialtime-domaindatatofrequency-domainoneatthetransmitterandtheotherasanopticalFouriertransformation(OFT)devicetorecoverthedataatthereceiver.Byusingtheunchangedspectralenvelopeinlinearopticalfibercommunication,theinitialdatacanberecovered.Throughsimulations,a10×100Gb/sintensitymodulateddirect-detection(IM-DD)densewavelengthdivisionmultiplexing(DWDM)systemover2000kmtransmissionwithoutthecompensationforpolarizationmodedispersion(PMD)anddispersionslopeisachieved,whichcanbeusedtoupgradethecurrent10-Gb/sIM-DDsystemtoa100-Gb/sonedirectly.

  • 标签: 传输系统 直接检波 PMD Gb 频域 光学傅里叶变换
  • 简介:A100-Gb/shigh-speedopticaltransmitterisproposedandexperimentallydemonstrated.Basedonfrequency-quadruplingtechnique,twosub-channelswithafixed50-GHzspacingareobtainedfromonelasersource.Usingreturn-to-zerodifferentialquadraturephase-shiftkeying(RZ-DQPSK)modulationformatandpolarizationmultiplexing(PolMux),onlylow-speedelectronicdevicesof12.5GHzareneededforthe100-Gb/stransmitter.Thiseliminatestheneedofultrahigh-speedoptoelectronicdevicesandthusgreatlyreducesthecost.Theexperimentalresultsshowthatthistransmittercanachievegoodperfor-manceindispersiontoleranceofa25-kmsinglemodefiber(SMF).

  • 标签: 光学通信 光电子装置 光谱效率 单模光纤
  • 简介:为满足性能良好、运行稳定、精度高的触摸屏在嵌入式系统中的广泛应用,提出了一种嵌入式系统的触摸屏驱动设计,这种方案基于S3C2410微处理器与触摸屏的硬件接口在嵌入式UCOS操作系统中的软件驱动实现,采用外部晶体管连接触摸屏到S3C2410的接口电路,并利用S3C2410的等待中断模式和自动X-Y坐标转换工作模式,读出与X-Y坐标有关的电压值。高效地完成了触摸状态的检测以及触摸数据的转换,其实现方法具有简便高效,易于实现等特点。

  • 标签: 嵌入式系统 触摸屏 ARM处理器 数转换器 控制寄存器
  • 简介:Alowcost8×10-Gb/stransmissionsystemover1500kmonconventionalfiberusingchirpedfiberBragggrating(CFBG)asdispersioncompensatorisdemonstrated.Thebiterrorrate(BER)below10-10at1500kmisobtained.Thechannelspacingis0.8nmandtheopticalamplifierspacingis100km.Only16erbium-dopedfiberamplifiers(EDFAs)areused.

  • 标签: 光纤传播 光栅 离散补偿 信道空间 光学放大器
  • 简介:Non-uniformstep-sizedistributionisimplementedforsplit-stepbasednonlinearcompensationinsingle-channel112-Gb/s16quadratureamplitudemodulation(QAM)transmission.Numericalsimulationsofthesystemincludinga20×80kmuncompensatedlinkareperformedusinglogarithmicstepsizedistributiontocompensatesignaldistortions.50%ofreductioninnumberofstepswithrespecttousingconstantstepsizesisobserved.Theperformanceisfurtherimprovedbyoptimizingnonlinearcalculatingposition(NLCP)incaseofusingconstantstepsizeswhileNLCPoptimizationbecomesunnecessarywhenusinglogarithmicstepsizes,whichreducesthecomputationaleffortduetouniformlydistributednonlinearphaseforallsuccessivesteps.

  • 标签: 非线性补偿 步长 相干检测 传输 非均匀分布 非线性计算
  • 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