Raws li fiber ntau optic networks tau tsim kom muaj kev nrawm dua, kev ncua ntev, thiab wavelength-division multiplexing (WDM), fibers tau siv nyob rau hauv qhov tshiab wavelength ranges, uas yog "bands". Fiber kis tau tus mob bands tau raug txhais thiab tus qauv, los ntawm cov thawj O-band mus rau U / XL-bands. Tsab ntawv xov xwm no yuav qhia txog qhov kev hloov pauv ntawm cov kab hluav taws xob sib kis tau zoo siv rau kev sib txawv ntawm kev sib tham hauv xov tooj.
Ntawm cov qhab no, O-band, tseem hu ua Original-band, yog thawj pawg siv hauv kev sib txuas lus kho qhov muag vim tias me me pulse broadening (me me dispersion); Ib hom fiber ntau kis tau tus mob pib nyob rau hauv "O-band" cia li saum toj no lub cutoff wavelength ntawm SM fiber ntau tsim los coj kom zoo dua ntawm qhov txo qis ntawm cov iav fiber ntau ntawm lub wavelengths ntev thiab muaj 1310nm diode lasers.
E-band sawv cev rau thaj tsam dej ncov thaum U / XL-band nyob ntawm qhov kawg ntawm lub qhov rais xa mus rau silica iav. E-band (dej-peak band) tseem tsis tau muaj pov thawj muaj txiaj ntsig tshwj tsis yog rau CWDM. Nws yog feem ntau siv los ua qhov txuas ntxiv ntawm O-band tab sis ob peb daim ntawv thov tau raug npaj thiab nws muaj zog heev rau kev tsim khoom. E-bands thiab U / XL-bands feem ntau raug zam vim tias lawv sib haum rau cov cheeb tsam kev sib kis loj.
Txhawm rau ua kom zoo dua qhov poob qis ntawm wavelength ntawm 1550nm, fiber ntau tau tsim los rau C-band. C-band feem ntau siv nrog rau kev txhim kho ntawm kev sib kis ntev ntev nrog EDFA thiab WDM thev naus laus zis. Raws li kev sib kis tau ntev dua thiab fiber ntau amplifiers pib siv es tsis txhob siv optical-to-electronic-to-optical repeaters, C-band ua qhov tseem ceeb dua. Nrog rau qhov tshwm sim ntawm DWDM (dense wavelength-division multiplexing) uas ua rau muaj ntau lub teeb liab sib koom ib leeg, kev siv C-band tau nthuav dav.
Nrog rau kev txhim kho ntawm fiber ntau amplifiers (Raman thiab thullium-doped), DWDM system tau nthuav dav mus rau L-band, leveraging lub wavelengths nrog qis qis attenuation tus nqi hauv iav fiber ntau nrog rau qhov ua tau ntawm optical amplification. Erbium-doped fiber ntau amplifiers (EDFAs, uas ua haujlwm ntawm cov wavelengths) yog ib qho tseem ceeb ntawm kev siv tshuab rau cov tshuab no. Vim tias WDM tshuab siv ntau lub wavelengths ib txhij, uas yuav ua rau muaj kev cuam tshuam ntau. Yog li no optical amplification technology yog qhia.
Txawm hais tias muaj kev cia siab zoo, tus naj npawb ntawm cov tshuab teeb tsa siv tag nrho-Raman cov kev daws teeb meem thoob ntiaj teb tuaj yeem suav ntawm ib sab tes. Nyob rau yav tom ntej, txawm li cas los xij, L-band tseem yuav ua pov thawj tias muaj txiaj ntsig. Vim tias EDFAs tsis tshua muaj txiaj ntsig hauv L-band, kev siv Raman amplification thev naus laus zis yuav rov hais dua, nrog rau cov twj tso kua mis wavelengths ze rau 1485nm.
Txawm hais tias CWDM tam sim no suav tias yog tus nqi qis ntawm WDM uas tau siv, feem ntau tsis ua haujlwm ntev. Qhov nrov tshaj plaws yog FTTH PON system, xa cov teeb liab nqes mus rau cov neeg siv ntawm 1490nm (hauv S-band) thiab siv tus nqi qis 1310nm kis tau tus nqi. Thaum ntxov PON systems kuj siv 1550 downstream rau TV, tab sis qhov ntawd tau hloov los ntawm IPTV ntawm cov teeb liab downstream ntawm 1490nm. Lwm lub tshuab siv kev sib xyaw ua ke ntawm S, C thiab L bands los nqa cov teeb liab vim qhov txo qis ntawm cov fibers. Qee lub tshuab txawm siv lasers ntawm 20nm sib nrug tshaj qhov ua tiav ntawm 1260nm txog 1660nm tab sis tsuas yog nrog cov dej tsis tshua muaj fiber ntau.
Txawm hais tias muaj ntau lub wavelength bands ntawm O-, S-, C- thiab L- bands tau tuaj rau hauv kev siv nrog kev nthuav dav ntawm cov tsheb khiav hauv xyoo tas los no, cov khoom siv fiber ntau optical rau O- thiab S-band wavelengths tsis tau paub txog. ntau xyoo vim muaj ntau yam kev nyuaj siab. C- thiab L-band feem ntau siv nyob rau hauv fiber ntau optic tes hauj lwm yuav ua si ntau thiab ntau lub luag hauj lwm tseem ceeb nyob rau hauv optical transmission system nrog rau kev loj hlob ntawm FTTH daim ntaub ntawv.
