Muyenera kumvetsetsa kusiyana pakati pa ulusi wa single-mode ndi ulusi wa multimode. Lero, tiyeni tikambirane za fiber optics zomwe zimagwiritsidwa ntchito kutumiza deta ngati zizindikiro za kuwala. Pali mitundu iwiri: single mode ndi multimode. Nkhaniyi ifotokoza mwatsatanetsatane magulu a single-mode ndi multimode ndi magwiridwe antchito, choncho pitirizani kuphunzira za kusiyana pakati pa single-mode ndi multimode.

Choyamba, mwina ndiyenera kuganizira za kukula kwa core. Ndikuganiza kuti single-mode ili ndi core yaying'ono, monga ma microns 9, pomwe multimode ndi yayikulu, mwina ma microns 50 kapena 62.5. Kukula kwa core mwina kumakhudza momwe kuwala kumayendera. Mu single-mode, popeza core ndi yaying'ono, mwina njira imodzi yokha ya kuwala imatha kufalikira, motero dzinalo. Multimode imalola ma modes angapo. Koma kodi "mode" imatanthauza chiyani apa? Ndikuganiza kuti mode ndi njira yomwe kuwala kumatha kudutsa mu ulusi. Chifukwa chake mu multimode, kuwala kumatha kutenga njira zingapo, zomwe zingayambitse kufalikira kwa modal. Pamenepo ndi pomwe ma modes osiyanasiyana amafika nthawi zosiyanasiyana, zomwe zimayambitsa kusokonekera kwa chizindikiro. Chifukwa chake single-mode, yokhala ndi njira imodzi yokha, imapewa izi. Izi zikutanthauza kuti single-mode imatha kuthana ndi bandwidth yayikulu pamtunda wautali.

Koma bwanji za gwero la kuwala? Ndikuganiza kuti single-mode imagwiritsa ntchito ma laser, omwe ndi olondola kwambiri ndipo amatha kuyang'ana kuwala mu core yaying'ono. Multimode ingagwiritse ntchito ma LED kapena ma laser otsika mtengo chifukwa core ndi yayikulu ndipo ndi yosavuta kuphatikiza kuwalako. Ma laser ndi okwera mtengo kwambiri, kotero ma transceiver a single-mode mwina ndi okwera mtengo kuposa a multimode.

Kutalika ndi chinthu china. Ngati single-mode ili ndi dispersion yochepa, imatha kuyenda mtunda wautali popanda kuwonongeka kwa chizindikiro. Multimode, yokhala ndi dispersion ya modal, ingakhale ndi mtunda waufupi kwambiri. Mwina ngati makilomita a single-mode ndi mazana a mamita a multimode? Koma ndiyenera kuyang'ana manambala enieni. Ndamva mawu monga OM3 ndi OM4 a multimode fibers, omwe akukhudzana ndi magwiridwe antchito awo. Izi mwina ndi miyezo ya ma grade osiyanasiyana a multimode, okonzedwa kuti azithamanga kwambiri pamtunda wina.

Bandwidth— single-mode iyenera kukhala ndi bandwidth yokwera chifukwa palibe modal dispersion. Chifukwa chake pakulankhulana kwachangu komanso kwakutali monga pakati pa mizinda kapena m'malo olumikizirana matelefoni, single-mode ndi yabwino. Multimode imagwiritsidwa ntchito m'malo osungira deta kapena ma netiweki am'deralo komwe mtunda ndi waufupi, ndipo mtengo wake ndi nkhani yaikulu.

Malinga ndi mtengo wake, ulusi wokha: mtundu umodzi ukhoza kukhala wofanana pamtengo, koma ma transceivers (monga ma SFP modules) ndi okwera mtengo kwambiri chifukwa cha ma laser. Ma transceivers a multimode ndi otsika mtengo, koma ulusiwo ukhoza kukhala wokwera mtengo pang'ono? Yembekezerani, ayi, ndikuganiza kuti ulusi umodzi ndi wotsika mtengo nthawi zina chifukwa ndi wosavuta? Kapena mwina ndalama zoyikira zimasiyana. Yembekezerani, kuyikira kungakhale kovuta pa mtundu umodzi chifukwa pakati ndi kakang'ono, komwe kumafuna zolumikizira zolondola komanso kulumikizana. Zimenezi zingapangitse kuyikira kukhala kokwera mtengo kwambiri, ngakhale ulusiwo wokha utakhala wokwera mtengo.

Mapulogalamu: single-mode ya mtunda wautali, telecom, ISPs. Multimode ya ma LAN, malo osungira deta, ma network aku campus. Komanso, mwina pakakhala kuti bandwidth yayikulu ikufunika koma pamafunika kuthamanga kwakanthawi kochepa. Monga kulumikiza ma seva mkati mwa malo osungira deta.

Kutalika kwa mafunde komwe kumagwiritsidwa ntchito: Nthawi zambiri mafunde a single-mode amagwiritsa ntchito 1310 nm ndi 1550 nm, pomwe ma multimode amagwiritsa ntchito 850 nm ndi 1300 nm. Kutalika kwa mafunde a single-mode kumatha kukhala ndi kuchepa kwa mphamvu, zomwe zimapangitsa kuti afike patali.

Palinso china chake chokhudza kufalikira kwa chromatic, komwe kumakhudza single-mode kwambiri pa mtunda wautali kwambiri, koma amagwiritsa ntchito ulusi wosinthidwa wa dispersion kapena compensators. Vuto lalikulu la Multimode ndi kufalikira kwa modal, komwe kumachepetsedwa pogwiritsa ntchito ulusi woyikidwa m'magawo pomwe refractive index imasintha pang'onopang'ono, kuchepetsa kufalikira kwa modal poyerekeza ndi step-index.

Ndipo pali mitundu yosiyanasiyana ya ulusi wa multimode, monga OM1, OM2, OM3, OM4, OM5. Iliyonse ili ndi mphamvu zosiyana za bandwidth ndi mtunda. OM3 ndi OM4 zimapangidwa bwino kuti zigwiritsidwe ntchito ndi ma VCSEL a 850 nm (vertical-cavity surface-emitting lasers) kuti zizitha kuthamanga kwambiri monga 10G, 40G, 100G Ethernet. OM5 ndi ya wavelength division multiplexing mu multimode.

Kotero kuphatikiza zonsezi: kukula kwapakati, gwero la kuwala, mtunda, bandwidth, mtengo, mapulogalamu, ndi miyezo. Njira imodzi yogwiritsira ntchito nthawi yayitali, yokwera mtengo, komanso yogwira ntchito kwambiri. Njira zambiri zogwiritsira ntchito mtunda waufupi, mtengo wotsika, zosavuta kuyika koma zimachepetsedwa ndi kufalikira kwa modal.

Ndiyeneranso kuwona ngati pali kusiyana kwina kulikonse, monga ma radius opindika kapena kulimba. Mwina single-mode imakhudzidwa kwambiri ndi ma bend chifukwa cha core yaying'ono, koma sindikutsimikiza. Multimode ikhoza kukhala yolekerera kwambiri pankhaniyi. Komanso, imagwirizana ndi zida zomwe zilipo. Ngati netiweki ikugwiritsa ntchito kale multimode, kukweza kungafunike kusintha fiber ndi transceivers.

Mfundo ina: kuteteza mtsogolo. Mtundu umodzi ukhoza kukulitsidwa kwambiri pakuwonjezeka kwa liwiro mtsogolo popanda kusintha ulusi, pomwe mitundu yambiri ikhoza kukhala ndi zoletsa pamene zosowa za bandwidth zikukulirakulira kuposa zomwe ulusi ungathe kuchita ndi kufalikira kwa modal.

Dikirani, koma ndi kupita patsogolo kwa ma multimode monga OM5, mwina amatha kupirira kuthamanga kwambiri pamtunda waufupi. Chifukwa chake kusankha kumadalira momwe amagwiritsidwira ntchito komanso kukula komwe akuyembekezeka.

Ndikufunika kupanga zonsezi kukhala kufananiza kogwirizana. Mwina yambani ndi kusiyana kwakukulu, kenako pitani kuzinthu zaukadaulo monga bandwidth, mtunda, mtengo, mapulogalamu, ndi zina zotero. Komanso, phatikizani tebulo lachidule kuti mugwiritse ntchito mwachangu.

Ndiloleni nditsimikizire manambala ena. Ma core a single-mode ndi 8-10 microns, multimode 50 kapena 62.5. Single-mode imagwiritsa ntchito magwero a laser (1310, 1550 nm), multimode imagwiritsa ntchito LED/VCSEL (850, 1300 nm). Mtunda waukulu: single-mode imatha kufika makilomita makumi, ngakhale makilomita 100 ndi zida zoyenera. Multimode ya 100M mpaka 550m kutengera muyezo (OM3/OM4). Mtengo: ma transceiver a single-mode ndi okwera mtengo kwambiri, koma mtengo wa fiber ndi wofanana kapena wokwera pang'ono? Kapena mwina fiber ndi yotsika mtengo, koma mtengo wonse wa system ndi wokwera chifukwa cha ma transceiver.

Komanso, bandwidth: single-mode ili ndi bandwidth yopanda malire pazifukwa zothandiza, pomwe multimode imachepetsedwa ndi modal dispersion. Chifukwa chake pa 10G, 40G, 100G, multimode imatha kuthana nayo koma pa mtunda waufupi. Single-mode imatha kuthana ndi liwiro limenelo pa mtunda wautali kwambiri.

Ponena za miyezo, single-mode imaphimbidwa ndi ITU-T G.652, G.653, ndi zina zotero, pomwe multimode ndi TIA-492-AAAB (OM1), ndi zina zotero.

Kukhazikitsa ndi kukonza: njira imodzi imafuna kulondola kwambiri, kotero mwina akatswiri ambiri, ndalama zambiri zoyambira kukhazikitsa. Njira zambiri zimakhala zosavuta kugwira ntchito nazo, mtengo wotsika wokhazikitsa.

Kotero kufananiza kwathunthu kungakhudze mbali zonsezi. Mwinanso tchulani za kusintha, monga momwe single-mode ikuchulukirachulukira ngakhale patali chifukwa cha kuchepa kwa mtengo wa optics, koma multimode ikadali yogwira ntchito ngakhale patali kwambiri.