Raws li cov neeg siv khoom sib txawv, cov kev pabcuam sib txawv, thiab kev tsim cov thev naus laus zis ntawm ntau theem, cov qauv ntawm kev sib txuas lus fiber ntau tuaj yeem muaj ntau haiv neeg.
Tam sim no, ib tug kuj loj ntawm cov ntaub ntawv system yog siv rau optical fiber digital kev sib txuas lus systems ntawm kev siv zog modulation / direct nrhiav tau (IM / DD).Lub hauv paus ntsiab lus thaiv daim duab ntawm cov kab ke no tau pom hauv daim duab 1. Raws li tuaj yeem pom los ntawm daim duab, qhov kev sib txuas lus ntawm qhov muag fiber ntau yog tsim los ntawm optical transmitter, optical fiber, thiab optical receiver.
Daim duab 1 Schematic daim duab ntawm optical fiber digital kev sib txuas lus system
Nyob rau hauv qhov point-to-point optical fiber kev sib txuas lus system, lub teeb liab kis tau tus mob txheej txheem: lub input teeb liab xa mus rau lub optical transmitter davhlau ya nyob twg yog hloov mus rau hauv ib tug code qauv haum rau kis tau tus mob nyob rau hauv lub kho qhov muag fiber tom qab tus qauv hloov dua siab tshiab, thiab qhov kev siv ntawm lub teeb. qhov chaw yog ncaj qha tsav los ntawm lub tsav Circuit Court Modulation, thiaj li hais tias lub optical fais fab tso zis los ntawm lub teeb qhov chaw hloov nrog lub input teeb liab tam sim no, uas yog, lub teeb qhov chaw ua kom tiav cov hluav taws xob / kho qhov muag hloov dua siab tshiab thiab xa cov khoom siv hluav taws xob kho qhov muag teeb liab mus rau fiber ntau optical. rau kev sib kis;ntawm cov kab ntawm kev sib txuas lus, tam sim no, ib leeg-hom optical fiber Qhov no yog vim nws cov yam ntxwv kis tau zoo dua;tom qab lub teeb liab mus txog qhov kawg tau txais, lub input optical teeb liab yog thawj zaug kuaj pom ncaj qha los ntawm photodetector kom ua tiav qhov kev hloov kho qhov muag / hluav taws xob, thiab tom qab ntawd nthuav dav, sib npaug, thiab txiav txim.Cov txheej txheem ntawm kev ua kom rov qab mus rau qhov qub hluav taws xob teeb liab, yog li ua tiav tag nrho cov txheej txheem sib kis.
Txhawm rau kom ntseeg tau qhov kev sib txuas lus zoo, yuav tsum tau muab cov khoom siv kho qhov muag rov qab ntawm qhov kev ncua deb ntawm cov transceivers.Muaj ob lub ntsiab ntawm optical repeaters nyob rau hauv optical fiber kev sib txuas lus, ib tug yog ib tug repeater nyob rau hauv daim ntawv ntawm kho qhov muag-hluav taws xob-kho qhov muag hloov dua siab tshiab, thiab lwm yam yog ib tug optical amplifier uas ncaj qha amplifies lub optical teeb liab.
Hauv kev sib txuas lus kho qhov muag fiber ntau, cov ntsiab lus tseem ceeb uas txiav txim siab qhov kev ncua deb yog qhov poob ntawm cov fiber ntau optical thiab kev sib kis bandwidth.
Feem ntau, qhov attenuation ntawm fiber ntau ib chav tsev ntev ntawm kev sib kis hauv fiber ntau yog siv los sawv cev rau qhov poob ntawm fiber ntau, thiab nws chav tsev yog dB / km.Tam sim no, cov tswv yim silica-raws li optical fiber ntau poob ntawm 2 dB / km hauv 0.8 mus rau 0.9 μm band;poob ntawm 5 dB / km ntawm 1.31 μm;thiab ntawm 1.55 μm, qhov poob tuaj yeem txo mus rau 0.2 dB / km, uas yog ze rau Qhov kev txwv theoretical ntawm SiO2 fiber ntau poob.Kev lig kev cai, 0.85 μm yog hu ua luv-yoj ntawm fiber optic kev sib txuas lus;1.31 μm thiab 1.55 μm yog hu ua qhov ntev-ntev ntawm kev sib txuas lus fiber ntau.Lawv yog peb qhov kev ua haujlwm qis qis ua haujlwm hauv kev sib txuas lus kho qhov muag fiber ntau.
Hauv kev sib txuas lus digital optical fiber, cov ntaub ntawv raug xa mus los ntawm qhov muaj lossis tsis muaj cov teeb liab kho qhov muag hauv txhua lub sijhawm.Yog li ntawd, qhov kev ncua deb kuj tseem raug txwv los ntawm fiber ntau kis bandwidth.Feem ntau, MHz.km yog siv los ua chav tsev ntawm kev sib kis bandwidth ib chav tsev ntev ntawm fiber ntau.Yog tias qhov bandwidth ntawm ib qho fiber ntau tau muab raws li 100MHz.km, nws txhais tau hais tias tsuas yog 100MHz bandwidth signals raug tso cai xa mus rau txhua mais ntawm fiber ntau.Qhov ntev ntawm qhov kev ncua deb thiab qhov me me ntawm kev sib kis bandwidth, qhov me me ntawm kev sib txuas lus muaj peev xwm.