Chiyambi cha RF pa dongosolo la ulusi

Chiyambi cha RF pa dongosolo la ulusi

RF pamwamba pa ulusindi imodzi mwa ntchito zofunika kwambiri za microwave photonics ndipo ikuwonetsa zabwino zosayerekezeka m'magawo apamwamba monga microwave photonic radar, astronomical radio telephoto, ndi kulumikizana kwa magalimoto amlengalenga osayendetsedwa ndi munthu.

RF pamwamba pa ulusiUlalo wa ROFAmapangidwa makamaka ndi ma transmitter a kuwala, ma optimera olandila ndi ma cable a kuwala. Monga momwe zasonyezedwera pa Chithunzi 1.

Ma transmitter a kuwala: Ma laser opereka mayankho ogawidwa (Laza ya DFB) amagwiritsidwa ntchito pa ntchito zotsika phokoso komanso zosinthasintha kwambiri, pomwe ma laser a FP amagwiritsidwa ntchito pa ntchito zotsika mtengo. Ma laser amenewa ali ndi ma wavelength a 1310nm kapena 1550nm.

Cholandirira kuwala: Kumapeto ena a ulalo wa ulusi wowala, kuwalako kumazindikirika ndi PIN photodiode ya cholandirira kuwalako, yomwe imasintha kuwalako kukhala magetsi.

Zingwe zowunikira: Mosiyana ndi ulusi wa multimode, ulusi wa single-mode umagwiritsidwa ntchito mu ma linear links chifukwa cha kufalikira kochepa komanso kutayika kochepa. Pa kutalika kwa mafunde a 1310nm, kuchepa kwa chizindikiro cha kuwala mu ulusi wa kuwala kumakhala kochepera 0.4dB/km. Pa 1550nm, ndi kochepera 0.25dB/km.

Ulalo wa ROF ndi njira yotumizira mauthenga yolunjika. Kutengera ndi mawonekedwe a kutumiza mauthenga kolunjika ndi kutumiza mauthenga owoneka, ulalo wa ROF uli ndi ubwino waukadaulo uwu:

• Kutayika kochepa kwambiri, ndi kuchepa kwa ulusi wochepera 0.4 dB/km

• Kutumiza kwa ultra-bandwidth ya fiber optical, kutayika kwa fiber optical sikudalira kuchuluka kwa ma frequency

Ulalowu uli ndi mphamvu yonyamula chizindikiro/bandwidth yokwera, mpaka DC mpaka 40GHz

• Kusokoneza kwa maginito (EMI) (Palibe kukhudzidwa kwa chizindikiro munyengo yoipa)

• Mtengo wotsika pa mita imodzi • Ulusi wa kuwala ndi wofewa komanso wosinthasintha, wolemera pafupifupi 1/25 ya ma waveguides ndi 1/10 ya zingwe za coaxial

• Kapangidwe kosavuta komanso kosinthasintha (ka makina ojambula zithunzi zachipatala ndi zamakina)

Malinga ndi kapangidwe ka chotumizira kuwala, makina a RF over fiber amagawidwa m'mitundu iwiri: modulation yolunjika ndi modulation yakunja. Chotumizira kuwala cha makina a RF over fiber olunjika chimagwiritsa ntchito laser ya DFB yolunjika, yomwe ili ndi ubwino wotsika mtengo, kukula kochepa komanso kuphatikiza kosavuta, ndipo yakhala ikugwiritsidwa ntchito kwambiri. Komabe, chifukwa cha chip cha laser ya DFB yolunjika, RF over fiber yolunjika ingagwiritsidwe ntchito kokha mu band yafupipafupi pansi pa 20GHz. Poyerekeza ndi modulation yolunjika, chotumizira chakunja cha RF over fiber optical chimapangidwa ndi laser ya DFB yafupipafupi imodzi ndi modulator ya electro-optic. Chifukwa cha kukhwima kwa ukadaulo wa electro-optic modulator, makina akunja a RF over fiber amatha kugwiritsa ntchito mu band yafupipafupi yoposa 40GHz. Komabe, chifukwa cha kuwonjezera kwamodulator yamagetsi, dongosololi ndi lovuta kwambiri ndipo silikugwirizana ndi kugwiritsa ntchito. Kupeza ulalo wa ROF, kuchuluka kwa phokoso ndi kuchuluka kwa mphamvu ndi zinthu zofunika kwambiri pa maulalo a ROF, ndipo pali kulumikizana kwapafupi pakati pa atatuwa. Mwachitsanzo, kuchuluka kwa phokoso lochepa kumatanthauza kuchuluka kwa mphamvu, pomwe kuchuluka kwa mphamvu sikungofunika kokha ndi dongosolo lililonse, komanso kumakhudza kwambiri magwiridwe antchito ena a dongosololi.