I-Optical fiber communication, njengenye yezinsika eziyinhloko zokuxhumana zesimanje, idlala indima ebalulekile kumanethiwekhi esimanje ezokuxhumana.
Ukuthambekela kokuthuthuka kokuxhumana kwe-fiber optical kungalindelwa kulezi zici ezilandelayo.
I-1.Ukuze ubone ukwanda komthamo wolwazi kanye nokudluliswa kwebanga elide, i-fiber yemodi eyodwa enokulahlekelwa okuphansi kanye nokuhlakazeka okuphansi kufanele kusetshenziswe.Njengamanje, i-G.652 i-fiber optical yemodi eyodwa evamile isetshenziswa kakhulu emigqeni yezintambo zenethiwekhi yenethiwekhi.Nakuba le fibre inokulahlekelwa okuncane okungu-1.55 μm, inenani elikhulu lokuhlakazeka elingaba ngu-18 ps / (nm.km).Kuthiwa lapho i-fiber yemodi eyodwa evamile isetshenziswa ku-wavelength ye-1.55 μm, ukusebenza kokudlulisela akulungile.
Uma i-zero-dispersion wavelength isuka ku-1.31 μm kuya ku-1.55 μm, ibizwa ngokuthi i-dispersion-shifted fiber (DSF), kodwa uma le fibre ne-erbium-doped fiber amplifier (EDFA) isetshenziswa kuhlelo lokuphindaphinda kwe-wavelength division multiplexing (WDM) , izoba Ngenxa yokungahambelani kwe-fiber, ukuxuba kwamagagasi amane kwenzeka, okuvimbela ukusetshenziswa okuvamile kwe-WDM, okusho ukuthi ukuhlakazeka kwe-fiber zero akulungile ku-WDM.
Ukuze ubuchwepheshe bokuxhumana kwe-fiber optical busetshenziswe ngempumelelo ohlelweni lwe-WDM, ukuhlakazeka kwe-fiber kufanele kuncishiswe, kodwa akuvunyelwe ukuba ngu-zero.Ngakho-ke, i-fiber yemodi eyodwa entsha eklanyelwe ibizwa ngokuthi i-non-zero dispersion fiber (NZDF), esukela ku-1.54 ~ Inani lokuhlakazeka ebangeni elingu-1.56μm lingagcinwa ku-1.0 ~ 4.0ps / (nm.km), eligwema indawo eyiziro yokuhlakazeka, kodwa igcina inani elincane lokuhlakazeka.
Izibonelo eziningi zibikwe esidlangalaleni kusetshenziswa isistimu yokudlulisela ye-NZDF's EDFA/WDM.
I-2.Amadivayisi we-Photonic asetshenziswa ezinhlelweni zokuxhumana ze-fiber optical nawo athuthuke kakhulu eminyakeni yamuva.Ukuze kuhlangatshezwane nezidingo zezinhlelo ze-WDM, amadivaysi omthombo wokukhanya we-multi-wavelength (MLS) athuthukiswe eminyakeni yamuva.Ihlela ngokuyinhloko amashubhu e-laser amaningi ngohlelo futhi yenza ingxenye ye-hybrid ehlanganisiwe yokubona nge-coupler yenkanyezi.
Ukuze uthole isiphetho sokwamukela sohlelo lokuxhumana lwe-fiber optical, isithwebuli saso sesithombe kanye ne-preamplifier ngokuyinhloko kuthuthukiswa ngendlela yokusabela kwejubane eliphezulu noma kwebhendi ebanzi.Ama-PIN photodiode asengahlangabezana nezimfuneko ngemva kokuthuthukiswa.Ezithonjeni zezithombe ze-broadband ezisetshenziswa kubhendi ye-wavelength ende engu-1.55μm, ishubhu le-metal semiconductor-metal photodetection tube (MSM) lakhiwe eminyakeni yamuva nje.Igagasi elihambayo lisabalalisa isithwebuli sesithombe.Ngokwemibiko, le-MSM ingathola i-78dB ye-3dB frequency bandwidth yamaza okukhanya angu-1.55μm.
I-preamplifier ye-FET cishe izothathelwa indawo i-high electron mobility transistor (HEMT).Kubikwa ukuthi isamukeli se-optoelectronic esingu-1.55μm sisebenzisa umtshina we-MSM kanye nenqubo ye-HEMT pre-amplified optoelectronic integration (OEIC) inebhendi yefrikhwensi engu-38GHz futhi kulindeleke ukuthi ifinyelele ku-60GHz.
3. Isistimu ye-PDH yokudlulisela iphuzu-kuya-iphuzu ohlelweni lokuxhumana lwe-fiber optical ayikwazanga ukuzivumelanisa nokuthuthukiswa kwamanethiwekhi ezokuxhumana esimanje.Ngakho-ke, ukuthuthukiswa kokuxhumana kwe-fiber optical maqondana nokuxhumana sekuyinto engenakugwemeka.
I-SDH ingumthethosisekelo wenethiwekhi entsha sha enezici eziyisisekelo zokuxhumana.Kuyinethiwekhi yolwazi olubanzi ehlanganisa ukuphindaphinda, ukudluliswa kwemigqa kanye nemisebenzi yokushintsha futhi inamakhono aqinile wokuphatha inethiwekhi.Njengamanje isetshenziswa kabanzi.