Hauv kev sib txuas lus kho qhov muag fiber ntau, Dispersion Compensation Module (DCM) (tseem hu ua Dispersion Compensation Unit, DCU) yog siv los them nyiaj dispersion, piv txwv li, los them nyiaj dispersion nyob rau hauv ib tug ntev heev kis fiber ntau. Feem ntau, qhov module no muab ib qho kev tawg (xws li, ib txwm dispersion nyob rau hauv 1600nm spectral cheeb tsam), tab sis tam sim no kuj muaj modules nrog tunable dispersion. Ntxig lub module rau hauv qhov txuas fiber ntau optic yog qhov yooj yim heev vim tias muaj cov khoom siv kho qhov muag ntawm cov tswv yim thiab cov zis. Lub tshuab hluav taws xob fiber ntau tuaj yeem siv los them nyiaj rau qhov poob, piv txwv li, erbium-doped fiber amplifier tuaj yeem siv rau hauv 1500nm kev sib txuas lus. Ib qho kev them nyiaj dispersion feem ntau yog muab tso rau ntawm ob lub amplifiers.
Lub dispersion them nyiaj module tuaj yeem tau txais los ntawm kev siv cov txheej txheem hauv qab no:
1. Ib txoj hauv kev yooj yim thiab yooj yim yog siv cov khoom siv kho qhov muag ntev, piv txwv li, dispersion-hloov kho qhov muag fiber ntau, thiab cua nws ntawm ib lub bobbin nrog txoj kab uas hla ntawm 100-200 hli. Cov fiber ntau optical siv tau tuaj yeem ua kom zoo kom nws tuaj yeem them nyiaj rau kev sib kis hauv 100km ntev kis tau tus mob fiber ntau, thiab qhov poob qis tsuas yog ob peb decibels.
2. Lwm cov qauv compact dua nrog tsawg doping poob yog kev siv chirped fiber Bragg gratings. Qhov loj dispersion tuaj yeem raug them los ntawm kev siv qhov ntev (tsawg centimeters) fiber ntau gratings. Dispersion tuning yog ua tau los ntawm kev sib txawv ntawm cov cuab yeej kub (built-in kub gradient).
3. Nyob rau hauv WDM systems, phased arrays rau ib co duab yog siv.
Qee yam tseem ceeb ntawm kev them nyiaj dispersion:
1. Cov tub ntxhais yog cov dispersion uas tuaj yeem muab tau, uas nyob ntawm qhov ntev ntawm cov khoom sib kis tau zoo thiab hom kev sib kis fiber ntau. Piv txwv li, dispersion-shifted kis tau tus mob fibers yuav tsum tau tsawg dispersion them nyiaj.
2. Dispersiontxoj kab nqes (kev txiav txim siab dua) txwv tsis pub muaj bandwidth, uas yog qhov tseem ceeb tshwj xeeb hauv WDM systems. Nyob ntawm seb hom kev sib kis ntawm fiber ntau, qhov sib txawv dispersion slopes yuav tsum tau. Txoj kab nqes loj heev dispersion tuaj yeem ua rau fiber ntau tsim nyuaj.
3. Qee zaum nws yog ntshaw kom cov dispersion yuav tunable.
4. Insertion poob yog tshwm sim los ntawm ob qho tib si nqus thiab tawg hauv cov fiber ntau, nrog rau kev koom tes los ntawm splices thiab connectors. Qhov kev poob no yuav tsum tau khaws cia me me li sai tau vim tias lawv yuav tsum tau nce siab amplifier thiab qhia lub suab nrov ntxiv.
5. Qee zaum, cov teebmeem optical nonlinear kuj yuav cuam tshuam. Cov fibers muaj zog dispersive tuaj yeem txo cov nyhuv no, thiab cov fibers luv luv txaus.
6. Hauv kev siv tswv yim, compact qauv yog qhov tseem ceeb heev. Kev them nyiaj fibers tuaj yeem ua rau lub qhov txhab nruj, tab sis qhov no kuj txwv los ntawm kev poob qis.
Ntawm cov ntaub ntawv ib txoj kab siab heev, kev them nyiaj rau hom polarization dispersion kuj yuav tsum tau. Qhov no yog qhov nyuaj dua, vim tias nws yuav tsum muaj kev tswj hwm ntawm lub xeev polarization ntawm lub teeb liab teeb liab, thiab kev kho kom tsim nyog ntawm lub sijhawm ncua.
