雨课堂学堂在线学堂云《Optical fiber communication technology（成都信息工程）》单元测试考核答案

第1题Weusethetermoptictorefertofrequenciesintheinfrared,visible,andultravioletportionsofthespectrum.Visiblewavelengthsextend______.Afrom0.4micrometerto0.7micrometerBfrom0.4micrometerto0.85micrometerCfrom0.7micrometerto0.85micrometerDfrom1.26micrometerto1.75micrometer第2题Theadventoflampsallowedtheconstructionofsimpleoptic-communicationssystems,anytypeof()isbasicallyanoptic-communicationssystem.AlampBindicatorlampClaserDneonlamp第3题Itwasnotuntil1970thatthefirsttruly()wasdevelopedandfiberopticcommunicationsbecamepractical.AfiberBlow-lossfiberCplasticfiberDmultimodefiber第4题Digitalmodulationinvolvestransmittinginformationindiscreteform.()第5题Inanycase,theinformationmustbeinopticalformbeforetransmissionforeitherelectronicoropticalcommunications.()第6题Assumingthatthelossofthesystemis-3dBandtheinputpoweris5mW,theoutputpoweris2mW.()第7题Inwhichphenomenondoestheparticlenatureoflightmanifest?AInterferenceanddiffractionBPhotoelectriceffectCBraggscatteringDPropagationofelectromagneticwaves第8题Inwhichphenomenondoestheparticlenatureoflightmanifest?AInterferenceanddiffractionBComptonscatteringCBraggscatteringDDeviationinamagneticfield第9题Inanexperiment,abeamoflightpassesthroughanarrowslit,formingadistinctinterferencepattern.Basedonthisobservation,lLightisaparticlebecauseonlyparticlescanforminterferencepatternswhenpassingthroughanarrowslit.第10题Theparticlenatureandwavenatureoflightaremutuallyexclusive第1题Whichofthefollowingbestdefinesmonochromaticwave?AAwavewithonlyonewavelengthBAwavewithonlyonefrequencyCAwavewithonlyonephasevelocityDAwavewithonlyoneamplitude第2题Whichofthefollowingstatementsaboutelectromagneticwavesistrue?AElectromagneticwavestravelfasterinavacuumthaninamedium.BElectromagneticwavestravelslowerinavacuumthaninamedium.CElectromagneticwavestravelatthesamespeedinavacuumasinamedium.DElectromagneticwavescannottravelthroughavacuumoramedium.第3题Whichofthefollowingstatementsistrueaboutlight?ALightisaparticlethatexhibitswave-likebehavior.BLightisawavethatdoesnothaveaparticlenature.CLightisaparticlethatdoesnothaveawavenature.DLightisneitheraparticlenorawave.第4题____isafringeininterferencepattern.AAdarkstripewheretwolightwavescanceleachotherout.BAbrightstripewheretwolightwavesoverlapandreinforceeachother.CAstripewherelightdiffractsoffanobstacle.DAstripewherelightreflectsoffamirror-likesurface.第5题Whatistheeffectofreflectiononthepolarizationstateoflight_____?AReflectiondoesnotchangethepolarizationstateoflightBReflectionchangesthepolarizationstateoflighttofullypolarizedCReflectionchangesthepolarizationstateoflighttopartiallypolarizedDReflectionchangesthepolarizationstateoflighttounpolarized第6题_____istheeffectofpassingunpolarizedlightthroughapolarizer?AThelightbecomesfullypolarizedinonedirectionBThelightremainsunpolarizedCTheintensityofthelightincreasesDThecolorofthelightchanges第7题_____WhatisBrewsterangle.ATheangleatwhichreflectedlightbecomesfullypolarizedBTheangleatwhichreflectedlightremainsunpolarizedCTheangleatwhichreflectedlightbecomespartiallypolarizedDNoneoftheabove第8题Whathappenstothepolarizationstateoflightwhenitreflectsfromasurface_____?AItremainsunchangedBItbecomesfullypolarizedCItbecomespartiallypolarizedDItbecomesunpolarized第9题Whatistherelationshipbetweentheamplitudeandphaseoftheelectricfieldcomponentsforcircularlypolarizedlight_____?AEqualamplitudeandaphasedifferenceofπ/2or3π/2BEqualamplitudeandaphasedifferenceofπ/4or5π/4CEqualamplitudeandnophasedifferenceDNoneoftheabove第10题Whatisthepolarizationstateoflightwhentheellipseisacircle_____?ALinearpolarizationBCircularpolarization.CEllipticalpolarizationDNoneoftheaboveAnswer:第11题_____determinestheshapeoftheellipse?AAmplitudeoftheelectricfieldcomponentsBPhasedifferencebetweentheelectricfieldcomponentsCPhasedifferenceandamplitudeoftheelectricfieldcomponentsDNoneoftheabove第12题_____istheshapeoftheellipsethatrepresentsthepolarizationstateoflight.ACircleBTriangleCEllipseDRectangle第13题Howcanpolarizedlightbedecomposed_____?AIntoxandycomponentsBIntolinearandcircularcomponentsCIntoincoherentandcoherentcomponentsDIntounpolarizedandpolarizedcomponents第14题Whatdoesunpolarizedlightmean_____?ALightwitharandompolarizationstateBLightwithallelectricfieldcomponentsoscillatinginthesamedirectionCLightwithallelectricfieldcomponentsoscillatingindifferentdirectionsDLightwithnoelectricfieldcomponents第15题Whentwocoherentlightbeamsinterfere,______istypicallyobserved?ADiffractionpatternBInterferencepatternCReflectionpatternDTransmissionpattern第16题______istheprinciplebehindtheformationofinterferencefringesinaninterferometer?ADiffractionoflightbytheinterferometer'smirrorsBInteractionoflightwithmatterintheinterferometerCSuperpositionofwavesfromdifferentsourcesDPolarizationoflightintheinterferometer第17题______determinesthecolorofthefringesinadouble-slitinterferencepattern.AThedistancebetweentheslitsBThewavelengthofthelightCTheintensityofthelightsourceDThedistancebetweentheslitsandtheobservationscreen第18题Whichofthefollowingbestdescribesdiffraction______?AWhenlightencountersobstacles,itfollowsthestraightestpathpossible.BWhenlightencountersobstacles,itdeviatesfromtheoriginaldirectionandspreadsintotheshadowarea.CWhenlightencountersobstacles,itreflectsofftheminamirror-likemanner.DWhenlightencountersobstacles,itpassesthroughthemwithoutanychangeindirection.第19题Whatisthedistancefromtheslitstotheobservationscreeninaninterferenceexperiment______?AItshouldbeassmallaspossibletoobserveinterferencefringesclearly.BItshouldbegreaterthanthedistancebetweentheslitstoobserveinterferencefringesclearly.CItshouldbeequaltothedistancebetweentheslitstoobserveinterferencefringesclearly.DItdoesn'tmatteraslongasthescreenisplacedperpendiculartothepropagationdirectionoflightbeamsfromtheslits.第20题______isthedifferencebetweeninterferenceanddiffraction?AInterferenceoccurswhenwavessuperimpose,whilediffractionoccurswhenwavesencounterobstacles.BInterferenceisconcernedwiththepathoflightrays,whilediffractionisconcernedwiththebehavioroflightwaves.CInterferenceproducespatternsofconstructiveanddestructiveinterference,whilediffractionproducesunevenintensitydistributioninboththeshadowandgeometricilluminationareas.DInterferenceisconcernedwiththephaseoflightwaves,whilediffractionisconcernedwiththeamplitudeoflightwaves.第21题______isthedifferencebetweenclassicalgeometricopticsandwaveoptics.AClassicalgeometricopticsassumeslightbehavesasparticles,whilewaveopticsassumeslightbehavesaswaves.BClassicalgeometricopticsfocusesonthepathoflight,whilewaveopticsfocusesonthebehavioroflightwaves.CClassicalgeometricopticsignoresdiffractioneffects,whilewaveopticstakesthemintoaccount.DClassicalgeometricopticsassumeslightbehavesaswaves,whilewaveopticsassumeslightbehavesasparticles.第22题Whatistherelationshipbetweeninterferenceanddiffraction______?ATheyarethesamephenomenon.BTheyarecompletelydifferentphenomena.CInterferenceisaspecialcaseofdiffraction.DDiffractionisaspecialcaseofinterference.第23题_____isNOTawaveopticalphenomenon?AInterferenceBDiffractionCReflectionDTransmission第24题Whichstatementbestdescribesthewave-particledualityoflight?______ALightbehavesasawaveinsomeexperimentsandasaparticleinothers.BLightiseitherawaveoraparticle,dependingonthecontext.CLightcannotexhibitbothwaveandparticlepropertiessimultaneously.DLightisneitherawavenoraparticle,butratheraquantumentity.第25题Howdoopticallensesworkaccordingtotheelectromagnetictheoryoflight?______ATheyscatterlightwavesrandomlyinalldirectionstoformanimageonascreenoreyeretina.BTheyrefractlightwavesusingtherefractiveindexdifferencebetweenairandglasstoformanimageonascreenoreyeretina.CTheydiffractlightwavesusingdiffractiongratingstoformanimageonascreenoreyeretina.DTheyabsorblightwavescompletelytoformanimageonascreenoreyeretina.第26题Whatistherelationshipbetweenthephasevelocityandgroupvelocityoflightwaves?______AThephasevelocityisalwaysgreaterthanthegroupvelocity.BThephasevelocityisalwayslessthanthegroupvelocity.CThephasevelocityandgroupvelocityareequaltoeachother.DThereisnorelationshipbetweenthephasevelocityandgroupvelocity.第27题Whatistherelationshipbetweenwavelengthandfrequencyofelectromagneticwavesaccordingtotheelectromagnetictheoryoflight?______AWavelengthandfrequencyaredirectlyproportionaltoeachother.BWavelengthandfrequencyareinverselyproportionaltoeachother.CWavelengthandfrequencyhavenorelationshipwitheachother.DWavelengthandfrequencyvaryrandomlywitheachother.第28题Whichequationdescribesthepropagationofmonochromaticlightwaves?_____ASchrodingerequationBMaxwell'sequationsCHooke'slawDNewton'ssecondlaw第29题Whichofthefollowingbestdefinestherefractiveindexofanopticalmedium_____?ATheratioofthespeedoflightinvacuumtothespeedoflightinthemedium.BTheratioofthespeedoflightinthemediumtothespeedoflightinvacuum.CTheratioofthewavelengthoflightinvacuumtothewavelengthoflightinthemedium.DTheratioofthewavelengthoflightinthemediumtothewavelengthoflightinvacuum.第30题______isthespeedoflightinvacuumaccordingtotheelectromagnetictheory.A3x10^8m/sB3x10^6m/sC3x10^4m/sD3x10^2m/s第31题Makephotonspassthroughasingleslitonebyone,iftimeisenoughLong,diffractionpatternswillappearonthefilm第32题Afterasinglephotonpassesthroughasingleslit,completediffractionwillappearonthefilmShootingpattern第33题Theeffectsgeneratedbyalargenumberofphotonsoftenexhibitvolatility第34题Letphotonspassthroughtheslitonebyone,andeachphotonwillmoveuniformlyinastraightlineonthesameorbit第35题Thehigherthefrequencyoflight,theeasieritistoobservediffractionphenomena第36题Photonswithhigherenergyexhibitmoresignificantfluctuations.第37题Individualphotonsarepronetoexhibitingparticlelikebehavior,whilealargenumberofphotonsarepronetoexhibitingwavelikebehavior.第38题Waveparticledualityreferstothephenomenonwherelightsometimesexhibitswavelikebehaviorandsometimesexhibitsparticlelikebehavior.第39题Thehigherthefrequencyoflightwaves,themorepronouncedtheparticlenature.第40题Thereflectionenergyoflightindicatestheparticlenatureoflight第41题Undertheilluminationofafluorescentlamp,wecanobservecoloredstripesonthesurfaceoftwotightlysqueezedglasspanels,orthroughtheslitofapencilplacedtogether,wecanobservecoloredstripesonthefluorescentlamp.Thesetwophenomena().AAllareinterferencephenomenaoflightBAllarediffractionphenomenaoflightCTheformerisaninterferencephenomenon,whilethelatterisadiffractionphenomenonDTheformerisadispersionphenomenon,whilethelatterisaninterferencephenomenon第42题Whatisthecorrectunderstandingofthewaveparticledualityoflight?ATheeffectsofalargenumberofphotonsoftenexhibitwavelikebehavior,whilethebehaviorofindividualphotonsoftenexhibitsparticlelikebehaviorBLightisawavewhenitpropagates,butittransformsintoparticleswhenitinteractswithmatterCWaveparticledualityisthefundamentalpropertyoflight,sometimesitswavelikenatureissignificant,andsometimesitsparticlelikenatureissignificantDHighfrequencylightisparticles,lowfrequencylightiswaves正确答案：AC第43题Whichofthefollowingstatementsiscorrectintheexperimenttoverifythewaveparticledualityoflight?AMakephotonspassthroughtheslitonebyone,andifthetimeislongenough,diffractionpatternswillbedisplayedonthefilmBAfterasinglephotonpassesthroughaslit,acompletediffractionpatternwillappearonthefilmCThemotionpathofphotonsthroughslitsisastraightlineDThefluctuationoflightisalawofmotionforalargenumberofphotons正确答案：AD第44题Usinggreenlighttoirradiateaphotoelectrictubecanproduceaphotoelectriceffect.Toincreasethemaximuminitialkineticenergyofthephotoelectronwhenescapingfromthecathode?ASwitchtoredlightirradiationBIncreasetheintensityofgreenlightCIncreasetheaccelerationvoltageonthephotocellDSwitchtopurplelightirradiation第45题certainmetalsurfaceemitselectronswhenexposedtogreenlight,anddoesnotemitelectronswhenexposedtoyellowlight.Basedonthisfact,whichofthefollowinglightcanemitelectronswhenirradiatedonthemetalsurface?APurplelightBOrangelightCBluelightDRedlight正确答案：AC第46题Whichofthefollowingstatementsiscorrectaboutthenatureoflight?ARegardingthenatureoflight,Newtonproposedthe"particletheory",Huygensproposedthe"wavetheory",andEinsteinproposedthe"photontheory",bothofwhichexplainthenatureoflightBhewaveparticledualityoflightreferstothefactthatitcanbeviewedasbothmacroscopicwavesandmicroscopicparticlesCTheinterferenceanddiffractionphenomenaoflightindicatethatlighthaswavecharacteristicsDThephotoelectriceffectindicatesthatlighthasparticleproperties正确答案：CD第47题Whichofthefollowingstatementsiscorrectregardingthephotoelectriceffectcausedbyabeamofgreenlightshiningonacertainmetal?AIftheintensityofgreenlightisincreased,thenumberofphotoelectronsescapingperunittimeremainsunchangedBIftheintensityofgreenlightisincreased,themaximuminitialkineticenergyoftheemittedphotoelectronswillincreaseCIfpurplelightisusedforirradiation,themaximuminitialkineticenergyoftheemittedphotoelectronswillincreaseDIfpurplelightisusedinstead,thenumberofphotoelectronsescapingperunittimewilldefinitelyincrease第48题Whichofthefollowingstatementsiscorrect?APhotonsandphotoelectronsarethesametypeofparticleBWhenphotonsinteractwithparticlesofmatter,theynotonlyfollowtheconservationofenergy,butalsotheconservationofmomentumCLighthasbothparticleandwavecharacteristics,whichareprobabilitywaves,notelectromagneticwavesDMacroscopicobjectsalsohavewavecharacteristics,whicharemechanicalwaves第49题Thefirstpersontoprovetheparticlenatureoflightis().AEinsteinBNewtonCHuygensDGauss第50题Theparticletheoryoflightwasproposedby().AEinsteinBNewtonCHuygensDGaussTesting2第1题Thefiberopticlong-distancenetworkinChinaisashighasA58%B68%C88%D98%第2题Thefirstopticalfiberusedintransmissionsystemwasinventedin1970.第3题Therelativerefractiveindexdifferencebetweenthecorerefractiveindexn1andthecladdingrefractiveindexn2isdefinedAn1-n2Bn1/n2C(n1-n2)/n1D(n1-n2)/n2第4题Themeridianplaneisdefinedastheplaneintersectingwiththefiberaxisandperpendiculartothefiberwall.第5题ThefollowingthreeformsofsteprefractiveindexfibersarerankedfromlargesttosmallestrefractiveindexstepasfollowsAAll-glassfiber,PCSfibers,All-plasticfiberBAll-plasticfiber,All-glassfiber,PCSfibers,CPCSfibers,All-plasticfiber,All-glassfiber,DAll-plasticfiber,PCSfibers,All-glassfiber,第6题Theopticalfiberwithlargernumericalapertureismoresuitableforapplications.第7题Whatisthemaineffectoftheabsorptionlossofopticalfibersintheshortwavelengthregion?AInfraredabsorptionBUVabsorptionCBendingattenuationDMeltingattenuation第8题Theintrinsicabsorptionattenuationcanbereducedbyreasonablyselectingthedopingmaterialoftheopticalfiberinthemanufacturingprocess.第9题Whichofthefollowingisnonlinearscattering?ARayleighscatteringBMilescatteringCBrillouinscatteringDOpticalscattering第10题Athighpowertransmission,stimulatedRamanscatteringandstimulatedBrillouinscatteringinthefiberwon'tresultinconsiderablelosses.第11题Whichofthefollowingisnotbelongtoconnectionlossofopticalfiber?APermanentopticalfiberconnectionBEmergencyconnectionCFlexibleconnectionDMacrobendingloss第12题Macrobendingiscausedbythenon-uniformityintroducedduringtheproductionprocessofthefiber,unevenpressureduringcabling,anddifferentialthermalexpansionandcontractionofdifferentpartsofthefiberduringusage,resultinginmicron-levelbendingalongthefiber'saxis.第13题Thecorrectstatementis:ATofacilitatethetransmissionoflightwavesinthecore,therefractiveindexofthecladdingmustbeequaltotherefractiveindexofthecore.BTofacilitatethetransmissionoflightwavesinthecore,therefractiveindexofthecladdingmustbegreaterthantherefractiveindexofthecore.Cofacilitatethetransmissionoflightwavesinthecore,therefractiveindexofthecladdingmustbesmallerthantherefractiveindexofthecore.D(a)Tofacilitatethetransmissionoflightwavesinthecore,therefractiveindexofthecladdingmustbegreaterthanthatofthecoatinglayer.第14题TheprinciplebehindconfininglightwithinthecoreofanopticalfiberwithcladdingisARefractionBTotalinternalreflectionattheboundaryofthecladding.CTotalinternalreflectionattheboundarybetweenthecladdingandthecoatinglayer.DReflectionfromtheopticalfiberplasticcoatinglayer.第15题Thegradient-indexfiberutilizestheprincipleoflightscatteringtotransmitlight第16题Therefractiveindexofthegradient-indexfibercoreisgenerallyslightlysmallerthanthatofthecladding.Post-classexercise2第1题Whenthefiberhasacertainradiusofcurvature,itwillproduce____.正确答案：:Radiationloss第2题Forabsorptionloss,itinvolvestheconversionofopticalcarrierenergyintootherformsofenergy,usuallythermalenergy.第3题Radiationattenuationisoccurwhenthefiberhasacertainradiusofcurvature.第4题Theradiationattenuationofopticalfibersoccurswhenthefiberhasalargerradiusofcurvature.第5题Microbendingofopticalfibersisprimarilycausedbythebendingofthefiberalongitsaxis.第6题Macrobendingisalargescalebendinginevitablyappearsintheproduction,connectionandconstructionofopticalcable.第7题Whichbandisknownfortheabsorptionofhydroxideions(OH-)leadingtoasharpincreaseinloss,alsoknownasthewaterpeak?AO-bandBE-bandCS-bandDU-band第8题Whatdoesthe"E"inE-bandstandfor?AExtendedBEfficientCEffectiveDExponential第9题Whichbandiswidelyusedinmetropolitanareanetworks,long-distance,ultralong-distance,andsubmarineopticalcablesystems?AO-bandBE-bandCS-bandDC-band第10题Whatdoesthe"O"inO-bandstandfor?AOriginalBOptimalCOverlappingDOperational第11题Linearscatteringisdividedinto____and____.正确答案：:Rayleighscattering正确答案：:Milescattering第12题Rayleighscatteringisnotintrinsicscattering第13题Inthe1.55μmband,thelosscausedbyRayleighscatteringstillreaches0.18-0.2dB/km,whichisstillthemaincauseofthelossinthisband.第14题Transitionmetalions,includingiron,cobalt,nickel,copper,manganese,chromium,etc.,haveastrongabsorptioneffectinthewavelengthrangeusedinopticalcommunication.第15题Scatteringlossesarecategorizedintolinearscatteringlossesandnonlinearscatteringlosses.第16题Typicallyinthefabricationofopticalfibers,covalentbondsdonotbreakwhenthefibermaterialissubjectedtosomekindofthermalexcitation第17题ThelossmechanismfortheOHionisthestretchingvibration,justasfortheabsorptionbytheSiObond.第18题Whichoftheseisnotoneofthethreewindowsoffiberopticcommunications?A1.39umB1.24umC0.85umD0.95um第19题Whichisnotpartoftherangeofsidebandabsorptionpeaksproducedbytheelectronicstructureofmetallicimpurities?A0.55umB0.38umC0.99umD1.05um第20题Absorptionlossesdonotincludewhichofthefollowing?AconnectionlossBultravioletabsorptionCinfraredabsorptionDintrinsicmaterialabsorption第21题Usingopticalfibermaterialswithahigherrefractiveindexcanreduceabsorptionlosses.第22题Inopticalfibercommunication,infraredlightwithlongerwavelengthsismoreeasilyabsorbed.第23题Opticalfiberabsorptionlossesprimarilyaffectthefrequencycharacteristicsoflightsignals.第24题Metalmaterialsaretypicallyaprimarycauseofopticalfiberabsorption.第25题Opticalfiberabsorptionlossesareindependentofthewavelengthoflight.第26题Howcanabsorptionlossesinopticalfibersbeminimized?AIncreasethelengthoftheopticalfiberBChoosematerialswithahighrefractiveindexCUsematerialswithlowlossesDIncreasetheintensityoflight第27题Opticalfiberabsorptionlossesleadtoareductioninthesignal'swhichcharacteristic?AAmplitudeBFrequencyCPolarityDPhase第28题Inopticalfibers,whichwavelengthrangeoflightismorepronetobeabsorbedbyglassmaterial?AVisiblelightBInfraredlightCUltravioletlightDLaserlight第29题Inopticalfibercommunication,whichmaterialiscommonlyresponsibleforcausingopticalabsorption?AQuartzBMetalCWaterDGlass第30题Whatprimarilycausesabsorptionlossesinopticalfibers?ARefractionBScatteringCAbsorptionDReflection第31题Accordingtothedistributionofrefractiveindex,itcanbedividedinto____and____opticalfibers.正确答案：:step正确答案：:gradient第32题Thecorediameterofthesingle-modefiberis____μm.正确答案：:10第33题Inopticalfibertransmission,signaltransmissionmainlydependson____.正确答案：:totalreflection第34题Accordingtothetransmissionmodeoflightinthefiber,thefibercanbedividedintosingle-modefiberandmulti-modefiber第35题Step-indexopticalfiberisprimarilyusedfordatastorageapplications.第36题Atpresent,thelossof1550μmcommercialopticalfiberislessthan________dB/km.A0.1B0.2C0.3D0.4第37题Theoperatingwavelengthoftheshort-wavelengthfiberisA0.6～0.8μmB0.8～0.9μmC1.0～1.7μmD2μm～2.2μm第38题Ifthecorerefractiveindexofastepfiberisn1=1.5andtherelativerefractiveindexdifference△=2%,thenthenumericalapertureNAofthefiberisequaltoA3B0.3C1.5D0.02第39题Thebasicstructureofstep-indexopticalfiberincludesthe________and________.ACoreandCladdingBFibercoreandCladdingCCoreandSheathDCoreandOpticallayer第40题Therefractiveindexchangeinstep-indexopticalfibercausesthe________,makingthemfollowaspecificpath.AScatteringBReflectionCInterferenceDDiffraction第41题Theall-plasticfiberisoftenreferredtoas____.正确答案：:polymeropticalfiber第42题Thewave-particledualityoflightis:____and____.正确答案：:volatility正确答案：:corpuscularproperty第43题Therefractiveindexchangeinstep-indexopticalfibercanbeusedfordirectionalpropagationoflightsignals.第44题Step-indexopticalfiberissuitableformultimodepropagation.第45题Therefractiveindexchangeinstep-indexopticalfiberistypicallyachievedbycontrollingthechemicalcompositionofthefibermaterial.第46题Theadvantageofstep-indexopticalfiberoverconventionalopticalfiberis:ALowerbandwidthBHigherlossCGreatertransmissiondistanceDSmallerrefractiveindex第47题Inthedesignofstep-indexopticalfiber,theregionwheretherefractiveindexchangesistypicallycalled:ACoreBCladdingCFibercoreDTransitionzone第48题Step-indexopticalfiberisprimarilyusedfor:ADatastorageBHigh-speedinterconnectionCHigh-energyphysicsexperimentsDChemicalanalysis第49题Instep-indexopticalfiber,theabruptchangeinrefractiveindexresultsin:ADiffusionoflightsignalsBReflectionoflightsignalsCDiffractionoflightsignalsDNormalpropagationoflightsignals第50题Whatisthemaincharacteristicofstep-indexopticalfiber?AMultimodepropagationBUniformrefractiveindexCAbruptchangeinrefractiveindexDReflectionoflightsignals第51题Thefirstlowlossopticalfiberwasmanufacturedby____companyintheUnitedStatesin____,withalossvalueof20db/km.正确答案：:Corning正确答案：:1970第52题Opticalfiberismadeof____.正确答案：:glass第53题Inthetube,JohnTyndallfoundthatlightcanbetransmittedina____shape.正确答案：:zigzag第54题Whatkindoflightphenomenondoessignaltransmissioninopticalfiberrelyon?Itreliesonaspecialreflectionphenomenon---____..正确答案：:totalreflection第55题Lighthaswaveparticleduality.Sometimestheexternalappearanceis____,andsometimestheappearanceis____.正确答案：:granular正确答案：:volatile第56题Theopticalfiberasthinashumanhairactuallyreferstoasingleopticalfiber,whichiscomposedofcore,claddingandcoating.第57题Thetheoreticalmaximumlossofopticalfiberisdeterminedbytheintrinsicabsorptionandintrinsicscatteringofitsmaterial.第58题Until1966,______,thefatherofopticalfiber,publishedafamouspaper,inwhichheclearlystatedthatthelossofopticalfibercouldbereducedto20db/kmbyimprovingthepreparationprocessandimprovingthepurityofthematerial.ANewtonBGaoKunCJohnTyndallDDr.kapani第59题______characterizethefluctuationoflight.AReflectionandrefractionBDiffractionandinterferenceCReflectionanddiffractionDRefractionanddiffraction第60题Whatphenomenacharacterizethegranularityoflight?Itisourcommon______.AreflectionandrefractionBdiffractionandinterferenceCreflectionanddiffractionDrefractionanddiffraction第61题Thestructureofgradientrefractiveindexfiberscanbedividedintosingle-modefibersandmulti-modefibers第62题Atpresent,thelossofopticalfibersat1550nmcanreacharound0.2dB/nm,approachingthetheoreticallimitoffiberloss.第63题Therefractiveindexinthecoreofamultimodegradientrefractiveindexfiberisintermittentlytransformed.第64题Thelowlosswindowsusedinfiberopticcommunicationareinthe1310mm,850nm,and1550nmbands第65题Accordingtothedifferentrefractiveindexdistributionofthefibercross-section,commonlyusedfiberscanbedividedintostepfibers,gradientfibers,single-modefibers,andmulti-modefibers第66题Accordingtothecause