专业英语

Part5OpticalFiberCommunication,WordsandExpressions,access/kses/vt.使用；存取；接近n.进入；使用权；通路randomaccess随机存取；随机访问accesscontrol访问控制accumulate/kjumjlet/vi.累积；积聚vt.积攒accumulateexperience获取经验；积累经验accumulatedensity堆积密度,WordsandExpressions,acoustic/kustk/adj.声学的；音响的；听觉的n.原声乐器；不用电传音的乐器acousticwave声波acousticvelocity声速allocation/lke()n/n.分配，配置；安置resourceallocation资源分配,WordsandExpressions,analogous/nlgs/adj.类似的，相似的；同功的；可比拟的analogousto类推为analogousproof类比证明annihilate/nalet/vt.消灭，歼灭；战胜；废止vi.湮灭；湮没annihilatecompletely全部消灭,WordsandExpressions,anomalous/nm()ls/adj.异常的；不规则的；不恰当的anomalousabsorption反常吸收，异常吸收anomalousdispersion反常色散同义词：abnormalarbitrary/bt(r)r/adj.数任意的；武断的；专制的arbitraryparameter任意参数arbitraryfunction随意函数；任意函数arbitraryarrangement随机排列,WordsandExpressions,asynchronous/eskrns/（non-aynchronous）adj.电异步的；不同时的；不同期的asynchronouscommunication异步通信；非同步通讯asynchronoustransfermode异步传输模式反义词：synchronousadj.同步的；同时的attenuation/,tenjen/n.物衰减；变薄；稀释attenuationcoefficient衰减系数noiseattenuation噪声衰减,WordsandExpressions,avalanche/vln/n.雪崩vt.雪崩vi.崩塌avalanchephotodiode雪崩光电二极管avalanchebreakdown雪崩击穿bandwidth/bndwt/n.电子物带宽；通信频带宽度gainbandwidth增益带宽,WordsandExpressions,bendingloss弯曲损耗boundelectron物束缚电子boundaryloss边界损耗,WordsandExpressions,category/ktg()r/n.种类，分类；数范畴productcategory产品类别；产品目录compensate/kmpenset/vi.补偿，赔偿；抵消vt.补偿，赔偿；付报酬compensatefor赔偿，补偿,WordsandExpressions,chromatic/krmtk/adj.彩色的；色品的；易染色的chromaticaberrationn.色差；像差chromaticfigure染色质象dispersion/dsp()n/n.散布；统计数离差；驱散dispersionrelation色散关系chromaticdispersion光色散,WordsandExpressions,core/k/n.核心；要点；果心；计磁心；纤芯vt.挖.的核corecompetence核心竞争力coupler/kpl/n.电子耦合器；联结器directionalcoupler定向耦合器opticalcoupler光耦合器,WordsandExpressions,cross-phasemodulation（XPM）交叉相位调制depletion/dplin/n.消耗；损耗；放血depletionregion电耗尽区；势垒区；阻挡层,WordsandExpressions,deregulation/di,regjlen/n.违反规定，反常；撤消管制规定airlinederegulation航空解制derivative/drvtv/n.化学衍生物，派生物；导数adj.派生的；引出的secondderivative二次导数partialderivative偏导数；偏微商词根：derive/drav/vt.源于；得自；获得vi.起源,WordsandExpressions,dielectric/,dalektrk/adj.非传导性的；诱电性的n.电介质；绝缘体dielectricconstant介电常数dielectricloss化介电损耗electron-holepair电子-空穴对,WordsandExpressions,fluctuation/,flktjuein/n.起伏，波动economicfluctuation经济波动voltagefluctuation电压波动harmonic/hmnk/adj.和声的；谐和的；音乐般的n.物谐波；和声harmonicgenerator谐波发生器harmonicanalysis谐波分析,WordsandExpressions,graded-indexfiber梯度折射率光纤group-velocitymismatch群速度失配,WordsandExpressions,heterodyne/het()r()dan/adj.外差的，外差法的n.外差法；外差振荡器heterodynereceiver外差接收机heterodynedetector外差检波器hybrid/habrd/n.杂种，混血儿；混合物adj.混合的；杂种的hybridrice杂交水稻hybridsystem混合系统,WordsandExpressions,interoperability/ntr,prblt/n.计互操作性；互用性interoperabilityprinciples互操作性原则；互通性原则词根：interoperable彼此协作的；能共同操作的；能共同使用的isolator/aisleit/n.电子隔离器；隔音装置；绝缘体vibrationisolator隔振器opticalisolator光频隔离器,WordsandExpressions,modal/md()l/adj.模式的；情态的；形式的n.莫代尔（一种新型纤维素纤维）modaldispersion模间色散modallogic模态逻辑moderate/md()rt/adj.稳健的，温和的；适度的，中等的；有节制的vi.变缓和，变弱vt.节制；减轻moderateintensity中等强度,WordsandExpressions,nonetheless/nnles/adv.尽管如此，但是nevertheless/nevles/adv.然而，不过；虽然如此conj.然而，不过opticalfiber光纤,WordsandExpressions,normalized/nrmlazd/adj.标准化的；正规化的；规格化的v.使规范化（normalize的过去分词）；使正常化normalizedfrequency归一化频率normalizedoffset归一化的偏置packet/pkt/n.数据包，信息包；小包，小捆；波包vt.包装，打包datapacket数据包wavepacket物波包；波群,WordsandExpressions,perturbation/,ptbe()n/n.数天摄动；不安；烦乱，扰乱perturbationtheory微扰理论perturbationapproximation微扰近似photocurrent/ft(),kr()nt/n.电子光电流photocurrentgenerator光电发生器photocurrentcharacteristics光电流特性,WordsandExpressions,refertoas称为，称作，把称作relativecore-claddingindexdifference相对纤芯-包层折射率差cladding/kld/n.包层；电镀；喷镀v.穿衣（clad的ing形式）claddingthickness覆盖厚度,WordsandExpressions,repeater/rpit/n.通信中继器；通信转发器；重复者impulserepeater脉冲转发器repeaterspacing中继距离resonance/rez()nns/n.力共振；共鸣；反响resonancefrequency谐振频率nuclearmagneticresonance核磁共振resonatorn.声共鸣器，共鸣体；共振器resonatev.共鸣；共振,WordsandExpressions,reyleighscattering瑞利散射simultaneously/,smltensl/adv.同时地achievedsimultaneously同时达到，同时获得developsimultaneously并举,WordsandExpressions,single-mode单模multi-mode多模step-indexfiber阶跃折射率光纤(SIF)step-indexmonomodefiber阶跃折射率单模光纤step-Indexmultimodefiber阶跃折射率多模光纤,WordsandExpressions,tunablesemiconductorlaser可协调的半导体激光器ultrashort/ltrt/adj.超短波的；极短的ultrashortwave超短波ultrashortpulses超短脉冲,Inanopticalcommunicationsystem,informationistransmittedbylightpropagationinsideanopticalfiberintheformofacodedsequenceofopticalpulses.Thesignalweakensduringpropagationbecauseoffiberloss.在光通信系统中，信息通过光在光纤中以编码序列的光脉冲的形式传播。由于光纤损耗，信号在传播过程中减弱。,Part5OpticalFiberCommunication,Thetransmissiondistancecanexceedafewthousandkilometersforsuchsystemsaslongasfiberdispersiondoesnotlimitit.Anovelapproachmakesuseofopticalsolitonsthatusefibernonlinearityforcompensatingfiberdispersion.对于这样的系统，只要光纤色散不限制它，传输距离就可以超过几千公里。一种利用光孤子的新颖方法是通过光纤非线性来补偿光纤色散。,5.1DevelopmentofOpticalCommunicationSystem,Initssimplestform,anopticalfiberconsistsofacentralcoresurroundedbyacladdinglayerwhoserefractiveindexisslightlylowerthanthatofthecore.在最简单的结构中，光纤由一个被包裹层包围的纤芯组成，其折射率略低于纤芯。,5.2OpticalFiberCharacteristics,Suchfibersaregenerallyreferredtoasstep-indexfiberstodistinguishthemfromgraded-indexfibersinwhichtherefractiveindexofthecoredecreasesgraduallyfromcentertothecoreboundary.这种光纤通常被称为“阶跃折射率光纤”，以区别它们和梯度折射率光纤，在梯度折射率光纤中，其纤芯的折射率逐渐从中心向纤心边界逐渐减小。,5.2OpticalFiberCharacteristics,5.2.1OpticalLosses光损耗Severalfactorscontributetothelossspectrum,materialabsorptionandRayleighscatteringcontributingdominantly.Otherfactorsthatmaycontributetothefiberlossarebendinglossesandboundarylosses(duetoscatteringatthecore-claddingboundary).（以上）几个因素导致了光谱损耗、材料吸收和瑞利散射。其他可能导致光纤损耗的因素是弯曲损耗和边界损耗（由于纤芯-包层边界的光散射）。,5.2OpticalFiberCharacteristics,5.2.2ChromaticDispersion色散Onafundamentallevel,theoriginofchromaticdispersionisrelatedtothecharacteristicresonancefrequenciesatwhichthemediumabsorbstheelectromagneticradiationthroughoscillationsofboundelectrons.在一个基本的层面上，色散的起源与介质通过束缚电子振荡吸收的电磁辐射的特征共振频率有关。,5.2OpticalFiberCharacteristics,5.2.2ChromaticDispersion色散Animportantfeatureofchromaticdispersionisthatpulsesatdifferentwavelengthspropagateatdifferentspeedsinsidethefiberbecauseofthegroup-velocitymismatch.Thisfeatureleadstoawalk-offeffectthatplaysanimportantroleinthedescriptionofthenonlinearphenomenainvolvingtwoormoreoverlappingopticalpulses.色散的一个重要特征是，由于群速度失配，不同波长的脉冲在光纤内以不同的速度传播。这一特性导致了一种离散效应，它在涉及两个或多个重叠光脉冲的非线性现象的描述中起着重要的作用。,5.2OpticalFiberCharacteristics,5.2.3FiberNonlinearities光纤非线性效应Theresponseofanydielectrictolightbecomesnonlinearforintenseelectromagneticfields,andopticalfibersarenoexception.Onafundamentallevel,theoriginofnonlinearresponseisrelatedtoaharmonicmotionofboundelectronsundertheinfluenceofanappliedfield.对于强烈的电磁场，任何电介质对光线的响应都是非线性的，光纤也不例外。在一个基本的层面上，非线性响应的起源与在应用场的影响下束缚电子的谐波运动有关。,5.2OpticalFiberCharacteristics,5.3.1ModeCharacteristics模式特征Inaddition,thefibercansupportacontinuumofunguidedradiationmodes.Althoughtheinclusionofradiationmodesiscrucialinproblemsinvolvingtransferofpowerbetweenboundedandradiationmodes,theydonotplayanimportantroleinthediscussionofnonlineareffects.此外，光纤可以支持无制导辐射模式的连续统一体。尽管对于涉及到有界模式和辐射模式之间的能量转移问题，包含辐射模式是至关重要的，但在非线性效应的讨论中，它们并没有发挥重要作用。,5.3PropagationofOpticalBeaminFiber,5.3.2OpticalPulsePropagationandPulseSpreadinginFibers光纤中的光脉冲传播和脉冲展宽Thecombinedeffectsofgroup-velocitydispersion(GVD)andself-phasemodulation(SPM)onopticalpulsespropagatinginsideafibercanbestudiedbysolvingapulse-propagationequation.通过求解脉冲传播方程，研究了在光纤中传播的光脉冲的群速度色散（GVD）和自相调制（SPM）的综合效应。,5.3PropagationofOpticalBeaminFiber,5.3.3DispersionManagement色散管理（操纵）Inafiber-opticcommunicationsystem,informationistransmittedoverafiberbyusingacodedsequenceofopticalpulseswhosewidthisdeterminedbythebitrateBofthesystem.在光纤通信系统中，信息借由光脉冲的编码序列通过光纤传输，其脉冲宽度由系统的比特率B决定。,5.3PropagationofOpticalBeaminFiber,5.3.4Solitons孤子、孤波Afascinatingmanifestationofthefibernonlinearityoccursthroughopticalsolitons,formedasaresultoftheinterplaybetweenthedispersiveandnonlineareffects.极好的光纤非线性表现是由光孤子产生的，这是由色散和非线性效应相互作用而形成的。,5.3PropagationofOpticalBeaminFiber,5.4.1StimulatedBrillouinScattering(SBS)受激布里渊散射SBSgeneratesaStokeswavepropagatinginthebackwarddirection.ThefrequencyoftheStokeswaveisdownshiftedbyanamountthatdependsonthewavelengthofincidentsignal.SBS产成一个在反方向传播的斯托克斯波。通过一个依赖于入射信号波长的量，该斯托克斯波的频率减小。,5.4ImpactofFiberNonlinearities,5.4.2StimulatedRamanScattering(SRS)受激拉曼散射SRSdiffersfromSBSinseveralways.First,itgeneratesaforward-propagatingStokeswave.SRS在很多方面与SBS不同。首先，它产生一个正向传播的斯托克斯波。,5.4ImpactofFiberNonlinearities,5.4.3Self-PhaseModulation(SPM)自相位调制TheintensitydependenceoftherefractiveindexleadstoSPM-inducednonlinearphaseshift,resultinginchirpingandspectralbroadeningofopticalpulses.折射率的强度依赖导致了由SPM引起的非线性相位偏移，从而导致了光脉冲的啁啾和光谱展宽现象。,5.4ImpactofFiberNonlinearities,5.4.4Cross-PhaseModulation(XPM)交叉相位调制5.4.5Four-WaveMixing(FWM)四波混频,5.4ImpactofFiberNonlinearities,AllOpticalNetworksarethoseinwhicheitherwavelengthdivisionortimedivisionisusedinnewwaystoformentirenetworkstructur