1. Keeb kwm ntawm ntau hom fiber ntau
Ntau hom fiber ntau yog thawj qhov ua tau fiber ntau, nws qhov loj dua cov hluav taws xob thiab ntau dua cov lej sib luag hauv xyoo 1970 nrog cov teeb ci LED ua thawj tiam ntawm kev sib txuas lus kho qhov muag tshiab, siv hauv kev sib txuas lus ntev thiab luv. Nrog kev tawm ntawm cov hom fiber ntau, ntau hom fiber ntau tom qab tau txais kev thov luv ntau yam vim yog tus nqi qis ntawm nws cov kab ke tag nrho.
Tus thawj multimode fiber siv tub ntxhais txoj kab uas hla ntawm 50um thiab ib tus kwv tij refractive index qhov sib txawv ntawm 1%. Vim tias qhov chaw loj heev qhov ntev ntawm LED, tus qauv tsim muaj fiber ntau tsis tuaj yeem ntes cov teeb pom kev zoo ntawm lub zog ntawm LED, yog li 62.5um ntau hom fiber ntau tau tsim. Lub 62.5um ntau hom fiber ntau muaj 2% tus txheeb ze refractive index qhov sib txawv, thiab nws cov lej aperture kuj nce. Lub teeb ci ntau los ntawm LED yog ua ke nrog cov hom fiber ntau. Hauv nruab nrab xyoo 1990, tus nqi qis VCSEL laser tau tsim. Vim tias cov yam ntxwv ntawm lub teeb pom me me thiab cov lej sib luag ntawm VCSEL nws tus kheej, cov hom fiber ntau nrog cov tub ntxhais txoj kab uas hla ntawm 50um nrog 1% tus txheeb ze qhov sib txawv ntawm qhov ntsuas tau rub rov qab rau daim ntawv thov dua, thiab tau siv dav hauv luv- nrug kev sib txuas lus fiber ntau txog tam sim no.
2. Raug kev tsim ntawm ntau hom fiber ntau
Yuav kom tau txais qhov zoo tshaj plaws kev faib ua qhov chaw, qhov tsis yooj yim ntawm qhov kev faib tawm ntawm cov pa multimode fiber siv cov duab ntawm parabola los yog ze-parabola. Txog kev khoov cov nyom multimode fiber ntau, kev tsim sab nrauv zawj feem ntau saws.
3. Cov ntsiab lus cuam tshuam rau bandwidth ntawm multimode fiber
Lub hauv paus tseem ceeb uas cuam tshuam rau bandwidth ntawm multimode fiber yog fiber ntau thiab lub teeb ci. Lub hauv paus ntawm optical fiber feem ntau muaj xws li cov khoom tawg thiab hom dispersion.
Vim tias cov yam ntxwv ntawm tus fiber ntau multimode nws tus kheej, muaj txog li 19 hom pawg uas tuaj yeem sib kis tau hauv cov kab hluav taws xob multimode, thiab kev tawg ntawm cov qauv tuaj yeem loj heev yog tias tsis tau tswj tsis tau. Yog tias VCSEL siv, hom kev faib tawm feem ntau yog cuam tshuam los ntawm EMB ntawm hom bandwidth; yog siv LED, nws yog sawv cev ntawm OFL BW ntawm kev txhaj tshuaj tag nrho.
Kev siv hom bandwidth thiab cov khoom tawg ntawm cov fiber ntau tuaj yeem tau txais los ntawm kev faib tawm tshwj xeeb ntawm cov khoom siv fiber ntau. Qhov ntsuas ntawm lub zog ntawm cov bandwidth, hom bandwidth thiab cov khoom tawg yooj yim tsis muaj qhov loj me, nyob ntawm lub teeb ci. Feem ntau hais lus, LED lub teeb thiab cov khoom tawg yog lub ntsiab tseem ceeb ntawm kev sib txuas bandwidth. Rau VCSEL, hom tam sim no bandwidth yog qhov tseem ceeb tshaj plaws ntawm kev sib txuas bandwidth.
Cov ntsiab lus los ntawm cov teeb ci VCSEL tuaj yeem hais txog nws cov ntiv nplhaib flux EF (Encircled flux). Lub ntsiab lus ntawm VCSEL' s s encircled flux yog raws li hauv qab no. Nws yog qhov sib xyaw ntawm cov teeb hluav taws xob li qub nrog rau cov ntxaib hluav taws xob, uas sawv cev rau kev faib hluav taws xob ntawm txhua lub zog hauv cov qauv.
Qhov faib ntawm nws EF yuav tsum nyob hauv ob lub thawv liab hauv daim duab hauv qab no. Yog tias EF hla lub npov liab ntawm sab xis, txoj kab sib txuas yuav tsawg zuj zus.
4. Multi-hom fiber ntau link bandwidth ntsuas
Nws yog qhov tseem ceeb heev los soj ntsuam cov kab txuas txuas ntawm cov kab ntsig siv fiber ntau thaum siv ntau hom fiber ntau rau cov xaib network, vim tias tus neeg siv tsis tuaj yeem kuaj tag nrho VCSEL lasers thiab tag nrho cov kab ua ke los ntawm ib qho. Raws li cov ntsiab lus tshwj xeeb ntawm multimode fiber thiab VCSEL laser, fiber ntau txuas bandwidth kev ntsuas yog pab tau kom paub cov qauv tsim txuas bandwidth.
5. Multimode fiber ntau teeb meem
Nrog rau qhov kev thov nce ntawm cov hauv kev bandwidth siab, ntau hom fiber ntau yuav tsis tuaj yeem ua kom tau raws li qhov xav tau nce ntawm bandwidth tus nqi hauv ob peb xyoos tom ntej vim nws tus kheej cov yam ntxwv. Ntxiv mus, kev tsim cov txheej txheem ntawm ntau hom fiber nws tus kheej yog qhov nyuaj thiab nws cov nqi yog siab, uas tsuas yog cia siab rau VCSEL laser nrog tus nqi tsawg. Yog tias tib hom VCSEL lasers ntawm tib tus nqi tau dhau los ua muaj dav hauv ob peb xyoos tom ntej no, nws yuav ua rau muaj kev hem thawj rau kev muaj ntau hom fiber ntau.
Lub neej yav tom ntej ntawm ntau hom fiber ntau yuav tsum siv tag nrho ntawm nws cov qauv siv ntau hom los nthuav cov npe ntau. Yog tias qhov no tuaj yeem kov yeej nyob rau yav tom ntej, kab tias keeb kwm yuav muab kauv los ntawm ntau hom mus rau ib hom-rov qab thiab rov qab mus rau hauv daim ntawv thov universal ntawm ntau hom.
