FiberOpticNewwordsandphrases

1fibern.纖維

fiberoptic(opticalfiber)光纖(光纖電纜)2innovationn.革新，技術(shù)革新，新方法3immunityn.抗擾性，免除性，免疫(性)immuneadj.免疫的;免受(傷害)的4directvt.引導(dǎo)，導(dǎo)引5propagatev.傳播6refractionn.折射，折射度

refractvt.折射refractiveadj.折射的7indexn.指數(shù)，指標(biāo)，索引

(pl.indices)refractiveindex（indexofrefraction）折射率8externaladj.外部的；n.外部,外面

externalinterference外界干擾9interceptionn.截取，竊聽，監(jiān)聽10abundantadj.豐富的,充裕的11perceivev.察覺,感知FiberOptic12appreciationn.了解,懂得13sinen.正弦14incidencen.入射

angleofincidence（incidenceangle）入射角15criticaladj.臨界的，決定性的，極限的

criticalangle臨界角16dielectricn.電介質(zhì),絕緣材料17waveguiden.波導(dǎo),波導(dǎo)管18coren.（光纖）纖芯19claddingn.包層20sheathn.外皮，護層21jacketn.護套，外殼22governv.支配，決定，起決定影響23assemblyn.裝配,組合FiberOptic24radiusn.半徑(pl.radii)25possessvt.有，具有，擁有26knotn.結(jié)點，節(jié)27diametern.直徑28wavelengthn.波長29nanometern.納米，毫微米30perpendicularadj.垂直的，正交的

perpendicularto與……垂直，垂直于31zigzagadj.之字形的，Z字形的32opaqueadj.不傳導(dǎo)的,不透明的33destructiveadj.破壞(性)的destructivelyadv.破壞地34modaladj.n.模態(tài)(的)，形式(上的)35bouncevi.反跳(彈);反射36broadenvt.加寬，擴展FiberOptic37differentiatevt.區(qū)分,區(qū)別38predefinen.預(yù)先確定（規(guī)定），預(yù)定義39precludevt.阻礙，妨礙40outlinevt.略述，概括地論述41uniformadj.均勻的，一致的42mono(前綴)單，單一，一monomoden.單模43dispersionn.色散44profilen.曲線，分布圖refractiveindexprofile折射率分布45devisevt.設(shè)計，發(fā)明46chromaticadj.有色的，彩色的chromaticdispersion色散1comeofage成年,到法定年齡,發(fā)達,充分發(fā)展2freedomfrom免除3attheedgeof在……的邊緣4Snell’slaw斯涅爾（折射）定律

FiberOptic5multimodefiber多模光纖6singlemodefiber(singlemodefiber)單模光纖7cladfiber包層光纖,涂層纖維8parallelto與……平行,平行于9lightray光線10lightbeam光束11backandforth來來往往地,來回地12modesofpropagation（propagationmode）傳播模，傳播波型13multimodepropagation多模傳播14opticalreceiver光接收器

opticalcommunicationreceiver光通信接收機15errorrate誤碼率FiberOptic16destructiveinterference破壞性干擾，相消(性)干擾17gradedindexfiber漸變折射率光纖

gradedindexmultimodefiber漸變折射率多模光纖18steppedindexfiber階躍折射率光纖19intermodaldispersion模間色散

FiberOptic

Opticalfibertransmissionhascomeofageasamajorinnovationintelecommunications.Suchsystemsofferextremelyhighbandwidth,freedomfromexternalinterference,immunityfrominterceptionbyexternalmeans,andcheaprawmaterials(silicon,themostabundantmaterialonEarth).FundamentalsofFiberOpticSystemsOpticalfibersguidelightrayswithinthefibermaterial.Theycandothisbecauselightraysbendorchangedirectionwhentheypassfromonemediumtoanother.Theybendbecausethespeedofpropagationoflightineachmediumisdifferent.Thisphenomenoniscalledrefraction.Onecommonexampleofrefractionoccurswhenyoustandattheedgeofapoolandlookatanobjectatthebottomofthepool.Unlessyouaredirectlyovertheobject,itappearstobefartherawaythanitreallyis.Thiseffectoccursbecausethespeedofthelightraysfromtheobjectincreasesasthelightrayspassfromthewatertotheair.Thiscausesthemtobend,changingtheangleatwhichyou

FiberOpticperceivetheobject.themtobend,changingtheangleatwhichyouperceivetheobject.YoucanobtainanappreciationforthemannerbywhichlightflowsbyfocusinguponSnell’sLaw.Snell’sLawHowopticalfibersworkcanbeexplainedbySnell’sLaw,whichstatesthattheratioofthesineoftheangleofincidencetothesineoftheangleofrefractionisequaltotheratioofthepropagationvelocitiesofthewaveinthetworespectivemedia.Thisisequaltoaconstantthatistheratiooftherefractiveindexofthesecondmediumtothatofthefirst.Writtenasanequation,Snell’sLawlookslikethis:sinA1/sinA2=V1/V2=K=n2/n1Inthisequation,A1andA2aretheanglesofincidenceandrefraction,respectively.V1andV2arethevelocitiesofpropagationofthewaveinthetwomedia.n1andn2aretheindicesofrefractionofthetwomedia.

TheparametersaredemonstratedgraphicallyinFig.12.1.Ineachcase,

A1istheangleofincidence,andA2istheangleofrefraction.Theindex

ofrefraction(n1>n2)ofrefractionofmaterial1,n1,isgreaterthantheindexofrefractionofmaterial2,n2.Thismeansthatthevelocityof

FiberOpticpropagationoflightisgreaterinmaterial2thaninmaterial1.Fig.12.1(a)demonstrateshowalightraypassingfrommaterial1tomaterial2isrefractedinmaterial2whenA1islessthanthecriticalangle.Fig.12.1(b)demonstratestheconditionthatexistswhenA1isatthecriticalangleandtheangleA2isat90［dg］.Thelightrayisdirectedalongtheboundarybetweenthetwomaterials.AsshowninFig.12.1(c),anylightraysthatareincidentatanglesgreaterthanA1ofFig.121(.b)willbereflectedbackintomaterial1withangleA2equaltoangleA1.TheconditioninFig.12.1(c)istheoneofparticularinterestforopticalfibers.

ExercisesⅠ.PleasetranslatethefollowingwordsandphrasesintoChinese.1.lightbeam2.propagationmode3.refractiveindexprofile4.chromaticdispersion5.opticalreceiver6.externalinterference7.errorrate8.dielectric9.lightray10.cladfiber11.destructiveinterference12.steppedindexfiber

光束傳播模折射率分布色散光接收器外界干擾誤碼率電介質(zhì),絕緣材料光線包層光纖，涂層纖維破壞性干擾，相消(性)干擾階躍折射率光纖ExercisesⅡ.PleasetranslatethefollowingwordsandphrasesintoEnglish.1.波導(dǎo)（管）2.臨界角3.納米4.光纖通信系統(tǒng)5.光纖傳輸6.單模光纖7.漸變折射率多模光纖

waveguidecriticalanglenanometeropticalcommunicationssystemopticalfibertransmissionsinglemodefiber(singlemodefiber)gradedindexmultimodefiberExercises8.波長9.斯涅爾定律10.折射率11.折射角12.破壞性干擾13.多模傳輸14.光通信接收機15.入射角16.光纖

wavelengthSnell’slawrefractiveindex(indexofrefraction)refractionangle(angleofrefraction)destructiveinterferencemultimodetransmissionopticalcommunicationreceiverangleofincidence(incidenceangle)fiberoptic(opticalfiber)

ExercisesⅢ.Fillintheblankswiththemissingword(s).1.Opticalfibertransmissionhascome

of

ageasamajorinnovationintelecommunications.2.Theraypropagates

in

thiszigzagfashiondownthecoreuntilitreachestheotherend.3.LightrayAentersthefiberperpendicular

to

thefaceofthecoreandparallel

to

theaxis.4.Inadditiontopointers,asignificantportionoftheoverheadbytes

in

theSTS1framearereservedformanagementdata,enablingnetworkmanagementfunctionstoincludeloopback,biterrorratetesting,andcollectionandreportingofperformancestatistics

tobe

carried(carried,tobecarried,carrying,havingcarried)withintheSONETframe.5.Thisisbecausemodaldelayspreadingbroadensthepulsesin

thetimedoain.

Exercises6.Raysenteringthefiber

at

differinganglesarerefractedvaryingnumbersoftimesastheymovefromoneend

to

theotherandconsequentlydonotarriveatthedistantend

with

thesamephaserelationshipaswhentheystarted.7.Theeffectofpulsespreadingistomakeitdifficultorimpossibleforanopticalreceivertodifferentiateonepulse

from

anotherafteragiventransmissiondistance.8.Becausemostopticalcommunicationssystemstransmitinformationin

digitalformconsistingofpulsesoflight,theeffectofmodaldelayspreadinglimitsthecapabilityofthefiber

totransport

(transporting,totransport,transported)recognizablepulses.9.Theresultofthedifferenceintherefractiveindiceskeepslight

flowing(flowing,flow,flowed,toflow)throughthecoreafteritgetsintothecore,evenifthefiberis

bent

(bent,bending,bend)or

tied(tied,tying,tie)intoaknot.10.Therayentersintothecladdingandpropagatesinto,orisabsorbed,into

thecladdingandjacket(whichisopaquetolight).

ExercisesⅣ.Answerthefollowingquestionsaccordingtothetext.1.Whatarethebenefitsofopticalfibertransmissionsystems?Opticalfibersystemsofferextremelyhighbandwidth,freedomfromexternalinterference,immunityfrominterceptionbyexternalmeans,andcheaprawmaterials(silicon,themostabundantmaterialonEarth).2.TelltheSnell’slawinyourownwordsinEnglish.Theratioofthesineoftheangleofincidencetothesineoftheangleofrefractionisequaltotheratioofthepropagationvelocitiesofthewaveinthetworespectivemedia.Exercises3.Pleasegivesometypicalparametervaluesdesignedforamultimodefiber.Followingaresometypicalvaluesforamultimodefiber:Anoperatinglightwavelengthof0.8micrometers(μm)Acoreindexofrefractionncof1.5Acladdingindexofrefractionnof1.485(=0.99nc)Acorediameterof50,62.5,or100μmAcladdingthicknessof37.5μm4.Whatisamultimodefiberandwhatisasinglemodefiber?Whatarethedifferencesbetweenthem?Singlemodefiber,alsoknownasmonomode,hasau