2016綜合布線基礎(chǔ)知識(shí)講義62

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

光纜的接合合Mechanical機(jī)械式Quick快速Littlespecializedequipmentrequired一般不需特特殊設(shè)備Newtechniquesandspliceconnectorshaveimprovedthelosspersplice(some<0.1dB)新技術(shù)和連連接器改善善了接合的的損耗Goodforemergencyfieldrepairs,lowvolumes應(yīng)急，小數(shù)數(shù)量Fusion熔結(jié)Requiresspecial,expensiveequipment需要特殊設(shè)設(shè)備Verylowloss(canbe<0.05dB)極低的損耗耗Theonlymethodforlong-haullinks長(zhǎng)距離鏈路路的唯一方方法激光產(chǎn)品的的級(jí)別ClassI－無(wú)危險(xiǎn)險(xiǎn)ClassIIa－觀看時(shí)時(shí)間小于1000秒則安全ClassII－長(zhǎng)期觀觀看有危險(xiǎn)險(xiǎn)ClassIIIa－直接觀觀看有嚴(yán)重重危害ClassIIIb－直接輻輻射對(duì)眼睛睛和皮膚有有嚴(yán)重傷害害ClassIV－直接觀觀看或散射射對(duì)眼睛和和皮膚有嚴(yán)嚴(yán)重傷害LASERWARNINGTIA/EIA568BStandardCable－電纜Maximumfiberlossperkm(at850nm)3.75dBMaximumfiberlossperkm(at1300nm)1.5dBMaximumfiberlossperkm(at1310nm)1.0dBMaximumfiberlossperkm(at1550nm) 1.0dBConnections(DuplexSCorST)－連接器Maximumadapterloss:0.75dBMaximumspliceloss:0.3dBLinkLengths(backbone)－鏈路長(zhǎng)度度SegmentHC-ICIC-MC62.5/125Multimode500m1500m50/125Multimode(underproposal)8/125Singlemode500m2500m光鏈路損耗耗的原因光纜的材料料純度材料密度的的變化光纜的彎曲曲程度宏觀彎曲(安裝問(wèn)題)微觀彎曲(產(chǎn)品制造問(wèn)問(wèn)題)光纜接合以以及連接的的耦合損耗耗不潔或連接接質(zhì)量不良良BarefiberThismakesyousaybadwords.密度改變DensityChange氣泡Bubble雜質(zhì)ImpurityMicrobend裂紋Macrobend造成衰減的的原因1.光纖本身的的缺陷耦合損耗CouplingLossesAreamismatchSpacinglossAxismisalignmentAngularmisalignmentLossesatsplicesandconnectors,includingtestequipmentconnectors:光纖的測(cè)試試光功率損耗耗

插入入損耗長(zhǎng)長(zhǎng)度傳傳輸時(shí)延延故障定位FIBERTEK?采用FIBERTEK?選件后，可可實(shí)現(xiàn)：損損耗與長(zhǎng)度度的測(cè)試需要雙端設(shè)設(shè)備測(cè)試