DWDM yog ib lub tshuab xa hluav taws xob hauv kev sib txuas lus fiber ntau. Nws siv ib qho khoom siv kho qhov muag los xa ntau lub teeb pom kev kho qhov muag ntawm qhov sib txawv wavelengths tib lub sijhawm, thiab faib cov wavelength ntau yam siv los ntawm cov khoom siv fiber ntau rau hauv ntau txoj kev. Cov channel xa cov teeb liab optical. Yog li ntawd, DWDM tau txhim kho kev sib kis tau zoo ntawm qhov kev sib txuas lus kho qhov muag. Cov tsos ntawm Erbium-doped fiber ntau amplifier (EDFA) ua rau DWDM kho qhov muag teeb liab kis tau tus mob deb.
1. Kev taw qhia txog lub hauv paus ntsiab lus ntawm EDFA
Erbium (Er) yog lub ntiaj teb tsis tshua muaj. Thaum ua ib qho khoom siv kho qhov muag, ib qho kev faib ua feem ntawm erbium yog ntxiv los ua ib qho erbium-doped optical fiber, uas muaj cov nyhuv ntawm amplification. Erbium ions muaj peb lub zog ua haujlwm: E1, E2 thiab E3. Ntawm lawv, E1 muaj lub zog qis tshaj plaws thiab hu ua hauv av xeev; E2 yog lub xeev metastable; E3 muaj lub zog siab tshaj plaws thiab dhau los ua lub xeev zoo siab. Nyob rau hauv cov ntaub ntawv ntawm tsis tau zoo siab los ntawm tej lub teeb, nws yog nyob rau hauv qis zog theem E1. Thaum lub laser ntawm lub twj tso kua mis lub teeb yog siv los txuas ntxiv excite lub erbium-doped fiber, cov hais nyob rau hauv lub xeev av yuav dhia mus rau ib tug siab zog theem thaum lawv nce zog. Yog hais tias nws hloov los ntawm E1 mus rau E3, vim hais tias cov particle tsis ruaj tsis khov ntawm lub zog ntawm E3, nws yuav hloov mus rau metastable zog theem tsis muaj hluav taws xob, thiab lub neej ntawm particle ntawm lub zog theem no kuj ntev, vim lub twj tso kua mis. Lub teeb qhov chaw Nrog kev zoo siab tas mus li, tus naj npawb ntawm cov khoom ntawm E2 lub zog theem yuav nce ntxiv, thaum lub zog ntawm E1 qib yuav txo qis. Thaum lub zog photon ntawm lub input optical teeb liab yog qhov sib npaug ntawm lub zog sib txawv ntawm E2 thiab E1, cov khoom hauv lub xeev metastable Nws yuav hloov mus rau hauv lub xeev hauv av hauv daim ntawv ntawm cov hluav taws xob txhawb zog, thiab radiate tib lub photons raws li cov photons. nyob rau hauv lub input optical teeb liab, yog li no zoo heev nce tus naj npawb ntawm photons, ua lub teeb liab input teeb ua ib tug muaj zog tso zis nyob rau hauv lub erbium-doped fiber Lub optical teeb liab realizes lub ncaj amplification ntawm lub teeb.
Tau kawg, qhov no kuj muaj qee qhov yuav tsum tau ua ntawm kev ua haujlwm wavelength ntawm lub twj tso kua mis lub teeb. Daim duab saum toj no qhia txog kev nqus spectrum ntawm erbium ions, los ntawm qhov nws tuaj yeem pom tau tias muaj cov khoom nqus nqus ntawm wavelengths ntawm 650nm, 800nm, 980nm, thiab 1480nm, thiab tuaj yeem siv rau hauv cov zaus bands. Nws raug suav tias yog qhov ua haujlwm wavelength ntawm EDFA twj tso kua mis lub teeb. Txawm li cas los xij, tom qab sib piv cov yam ntxwv xws li kev ua tau zoo, 980nm thiab 1480nm semiconductor lasers yog qhov tsim nyog dua li siv lub teeb ci rauEDFA. Piv nrog rau 1480nm, 980nm muaj qhov nce siab thiab tsis tshua muaj suab nrov, thiab tam sim no yog qhov nyiam siv lub tshuab nqus dej rau fiber ntau amplifiers. Muaj ntau ntau hom kev siv hauv EDFA. Nws yog lub npe hu ua seb lub zog tso tawm los ntawm lub twj tso kua mis lub teeb qhov chaw yog txhaj rau hauv erbium-doped fiber nyob rau hauv tib txoj kev raws li cov input optical teeb liab zog. Nws tuaj yeem muab faib ua rau pem hauv ntej twj thiab rov qab twj tso kua mis. txoj kev, thiab ob txoj kev twj tso kua mis.
Txoj kev siv ob txoj kev muaj qhov zoo ntawm kev xa mus rau pem hauv ntej thiab thim rov qab, yog li txoj kev no tuaj yeem tsis tsuas yog ua rau lub teeb pom kev sib npaug sib npaug hauv cov khoom siv kho qhov muag, tab sis kuj los ntawm qhov kev xav ntawm cov zis hluav taws xob, cov zis hluav taws xob ntawm ib qho twj tso kua mis yog 14dBm, thiab Lub zog tso zis ntawm bidirectional pumping yog 14dBm. Lub twj tso kua mis tuaj yeem ncav cuag l 7dBm. Ntxiv mus, bidirectional twj tso kua mis muaj qhov zoo tshaj plaws amplification efficiency, thiab co-directional twj tso kua mis muaj lub suab qis tshaj.
2. Kev siv EDFA hauv DWDM system
2.1. EDFA yog siv los ua preamplifier
Thaum tau txais qhov kawg ntawm wavelength division multiplexing, txhawm rau them nyiaj rau qhov poob ntawm demultiplexer thiab qhov txo qis ntawm cov neeg txais kev xav vim qhov nce ntawm tus nqi, lub suab nrov qis optical preamplifier yuav tsum tau teeb tsa ua ntej demultiplexer. Thaum kawg tau txais, EDFA yog siv los ua tus preamplifier rau PIN thiab APD. Thaum cov channel tus nqi siab li 2.5Gbit / s, piv nrog tsis muaj optical preamplifier, qhov rhiab heev ntawm tus txais yuav nce li ntawm 10 npaug.
2.2. EDFA yog siv los ua lub suab nrov nrov
EDFA yog siv los ua ib lub zog amplifier, uas muaj qhov zoo ntawm lub zog tso zis loj, cov zis ruaj khov, tsis tshua muaj suab nrov, dav nce ntau zaus, thiab saib xyuas yooj yim. Nws yog muab tso rau ntawm qhov muag transmitter ncaj qha mus rau amplify lub teeb liab ntawm lub optical transmitter. Lub hwj chim amplifiers tuaj yeem siv ib leeg lossis ua ke. Tom qab tau nthuav dav los ntawm EDFA, qhov tso zis hluav taws xob ntawm qhov kawg xa tuaj yeem nce los ntawm qhov kev txiav txim ntawm qhov loj, uas ua rau lub zog nkag mus rau fiber ntau.
2.3. EDFA yog siv los ua ib kab amplifier
Hauv kev sib txuas lus kho qhov muag, dispersion thiab poob txwv qhov kev ncua deb thiab muaj peev xwm ntawm kev sib txuas lus. Txhawm rau txo qhov cuam tshuam ntawm dispersion, kev them nyiaj dispersion tuaj yeem ua tau. Tom qab ntxiv cov dispersion compensating fiber ntau, qhov insertion attenuation yog nce ntxiv, yog li qhov ntxig attenuation yuav tsum tau them nrog lub tshuab hluav taws xob kho qhov muag. SivEDFARaws li cov kab amplifier tuaj yeem ua rau muaj qhov rov ua dua tshiab, thiab tseem tuaj yeem hloov kho qhov muag khoom kim dua.
3. Cov lus xaus
DWDM yog ib qho tshwj xeeb multiplexing txoj hauv kev sib txuas lus fiber ntau optical. Txoj kev no tuaj yeem siv tag nrho ntawm qhov dav-tsawg-tsawg thaj tsam ntawm cov khoom siv kho qhov muag fiber ntau, thiab tuaj yeem yooj yim ob npaug ntawm qhov nce ntxiv yam tsis tau hloov cov kab sib txuas lus kho qhov muag uas twb muaj lawm. Lub peev xwm ntawm fiber optic kev sib txuas lus systems. Tam sim no EDFA thiab DWDM tau dhau los ua qhov tseem ceeb ntawm kev txhim kho kev sib txuas lus kho qhov muag fiber ntau, sawv cev rau tiam tshiab ntawm kev sib txuas lus fiber ntau.
