第十一章關(guān)于光纖的測(cè)試光纖與銅纜的對(duì)比光纖基礎(chǔ)知識(shí)光纖的選用影響衰減的因素光纖測(cè)試設(shè)備

FiberOpticAdvantages

?光纖與銅纜的對(duì)比項(xiàng)目光纖（FIBER）銅纜（COPPER）線纜價(jià)格低較高抗電磁/射頻（EMI/RFI）干擾能力不會(huì)被干擾NEXT、FEXT等連接器抗電磁/射頻（EMI/RFI）干擾能力不存在總要被考慮接地回路不存在總要被考慮損耗低相對(duì)高帶寬高正在提高溫度穩(wěn)定性可能是個(gè)問(wèn)題可能是個(gè)問(wèn)題重量非常輕可能是個(gè)問(wèn)題易于安裝熔接困難比較容易安裝及維修工具的價(jià)格高低網(wǎng)卡價(jià)格光/電/光轉(zhuǎn)換部件昂貴路由器便宜放大器價(jià)格光/電/光轉(zhuǎn)換部件昂貴測(cè)試工具價(jià)格昂貴的OTDR認(rèn)證測(cè)試要求損耗、傳輸延遲和長(zhǎng)度單根或成對(duì)測(cè)試測(cè)試項(xiàng)目較多，可同時(shí)雙向多線對(duì)測(cè)試光纖基礎(chǔ)知識(shí)—電磁譜Frequency(Hz)UV可見(jiàn)光(750-380nm)X-RaysIRAMRadioWavelength(m)101210810141010101610181UHFVHF10610-310-9常用的光波長(zhǎng)(660,850,1300,1310,&1550nm)光纖基礎(chǔ)知識(shí)—波長(zhǎng)的選擇FirstWindowSecondWindowThirdWindow波長(zhǎng)(nm)8001200160008Loss(dB/km)4多模(MD) 工作于850nm和1300nm單模(SM) 工作于1310nm和1550nm多模與單模光纖MULTIMODEFIBER–HugeVolumeShortDistance<2kmSINGLEMODEFIBER–HugeVolumeLongDistanceFrom2kmto100kmCoreCladdingCoating

MultimodeFiber

PoweredbyLEDsandVCSELsat850nmand1300nmLowcostelectronicsUsuallyHasORANGEJacketingShortDistances(<2km)Greatfor:LocalAreaNetworks,CCTV,CampusAreaNetworks,OfficesandManufacturingInexpensiveforShortDistances,ExpensiveforLongDistanceCoreDiameters:50um,62.5um&100um

SinglemodeFiber

PoweredbyLasersat1310nm,1550nmand1625nmHighPowerLongDistance–2kmto100kmGreatfor:WideAreaNetworks,Metro.AreaNetworks,CATV,Utilities&TelcosInexpensiveforLongDistanceComparedtoCopper,ExpensiveforShortDistanceCoreDiameter:9umUsuallyhasYELLOWJacketing光纜結(jié)構(gòu)表皮(材料PVC)抗拉材料緩沖填充物核

FiberOpticConnectors

光纜纜的的接接合合Mechanical機(jī)械械式式Quick快速速Littlespecializedequipmentrequired一般般不不需需特特殊殊設(shè)設(shè)備備Newtechniquesandspliceconnectorshaveimprovedthelosspersplice(some<0.1dB)新技技術(shù)術(shù)和和連連接接器器改改善善了了接接合合的的損損耗耗Goodforemergencyfieldrepairs,lowvolumes應(yīng)急急，，小小數(shù)數(shù)量量Fusion熔結(jié)結(jié)Requiresspecial,expensiveequipment需要要特特殊殊設(shè)設(shè)備備Verylowloss(canbe<0.05dB)極低低的的損損耗耗Theonlymethodforlong-haullinks長(zhǎng)距距離離鏈鏈路路的的唯唯一一方方法法激光光產(chǎn)產(chǎn)品品的的級(jí)級(jí)別別ClassI－無(wú)無(wú)危危險(xiǎn)險(xiǎn)ClassIIa－觀觀看看時(shí)時(shí)間間小小于于1000秒則安安全ClassII－長(zhǎng)長(zhǎng)期觀觀看有有危險(xiǎn)險(xiǎn)ClassIIIa－直直接觀觀看有有嚴(yán)重重危害害ClassIIIb－直直接輻輻射對(duì)對(duì)眼睛睛和皮皮膚有有嚴(yán)重重傷害害ClassIV－直直接觀觀看或或散射射對(duì)眼眼睛和和皮膚膚有嚴(yán)嚴(yán)重傷傷害LASERWARNINGTIA/EIA568BStandardCable－電纜纜Maximumfiberlossperkm(at850nm)3.75dBMaximumfiberlossperkm(at1300nm)1.5dBMaximumfiberlossperkm(at1310nm)1.0dBMaximumfiberlossperkm(at1550nm)1.0dBConnections(DuplexSCorST)－連接接器Maximumadapterloss:0.75dBMaximumspliceloss:0.3dBLinkLengths(backbone)－鏈路路長(zhǎng)度度SegmentHC-ICIC-MC62.5/125Multimode500m1500m50/125Multimode(underproposal)8/125Singlemode500m2500m光鏈路路損耗耗的原原因光纜的的材料料純度材料密密度的的變化化光纜的的彎曲曲程度度宏觀彎彎曲(安裝問(wèn)問(wèn)題)微觀彎彎曲(產(chǎn)品制制造問(wèn)問(wèn)題)光纜接接合以以及連連接的的耦合合損耗耗不潔或或連接接質(zhì)量量不良良BarefiberThismakesyousaybadwords.密度改變DensityChange氣泡Bubble雜質(zhì)ImpurityMicrobend裂紋Macrobend造成衰衰減的的原因因1.光纖本本身的的缺陷陷耦合損損耗CouplingLossesAreamismatchSpacinglossAxismisalignmentAngularmisalignmentLossesatsplicesandconnectors,includingtestequipmentconnectors:光纖的的測(cè)試試光功率率損耗耗插插入入損耗耗長(zhǎng)長(zhǎng)度度傳傳輸輸時(shí)延延故障定定位FIBERTEK?采用FIBERTEK?選件后后，可可實(shí)現(xiàn)現(xiàn)：損損耗與與長(zhǎng)度度的測(cè)測(cè)試需要雙雙端設(shè)設(shè)備測(cè)測(cè)試測(cè)試：：測(cè)試功功率以以及連連接器器的損損耗操作簡(jiǎn)簡(jiǎn)單