,
4. Phan lo~i cap quang ;;
Cap quang Singlemode (SM) co duong kinh core kha nho (khoang 9µm), su d1,mg ngu6n phat laser truySn tia sang xuyen su6t vi v~y tin hi~u it bi suy hao va co t6c d9 kha l&n. SM thuong ho~t d9ng & 2 bu&c song (wavelength) 1310nm,
1550nm.
Cap quang Singlemode truySn duqc du li~u v&i khoang each khong gi&i rM xa, duqc cac don vi viSn thong su d\mg dS truySn du li~u trong h~ th6ng cua hQ. Hi~n nay cac djch V\l viSn thong hi~n nay duqc rfit dong dao nguai dan su dvng nen cac nha cung cfip dich V\l lien tl_,lc phai m& r(mg h~ th6ng truySn dfin quang cua h9 dS co thS dap lmg nhu cAu cua khach hang, do v~y da lam cho cap quang Singlemode tr& nen rfit phf> dvng, h~ thanh h~ di rfit nhiSu.
Cap quang Multimode (MM) co duong kinh core l&n hon SM (khoang 50µm, 62.5 µm). MM su d\mg ngu6n sang LED (Light Emitting Diode) ho~c laser dS truySn tia sang va thuong ho~t d(mg & 2 bu&c song 850nm, 1300nm; MM co khoang each kSt n6i va t6c d(> truySn d~n nho hon SM.
Cap quang Multimode hi~n nay duqc su d1.mg r(>ng rai trong cac lmg dvng truySn du li~u v&i khoang each :s 5Km, thuong duqc cac doanh nghi~p, ca quan su dvng
trong cac h~ th6ng m~ng n(>i b9, truySn thong trong cong nghi~p
(Step = x )0 ;;i c~i~~ :i;n~i;:i~:;ut~r~~1~ ..,..[_· .. _ _ _ ..,.._..,..__,,_.:_::,•..' .. _,_·-_·_•·••,...,····..,.;1,
index). Cac tia sang ki~u Step index truySn theo Mu!lit'r,\):j£ Srep~il)d;~;;
: : :11t~ Fl ~:~~1~:~~~·~!t;r~~ p---<><-;-........... -<-.. · -s- ~-7]
kiSu Graded index truySn dfin theo duong cong
va h(>i t\,l t~i m(>t di~m. Do do Graded index it I .·
suy hao va co t6c d9 truySn d~n cao hon Step ;:::========= .. =========. ==::::::·
index. Graded index duqc su dvng kha phf> biSn. I
Sm9t&.rnL'>dB
·····································
TruySn d~n tin hi~u tren cap quang co hai d~ng don cong (simplex) va song cong ( duplex). Simplex truySn tin hi~u chi 1 chiSu. Duplex co thS truySn nh~n tin hi~u 1 chiSu ban song cong (half-Duplex) ho~c ca 2 chiSu song cong toan phk (full-Duplex) Duplex & cung thm diSm tuy theo each cfiu hinh.
ON lm lt:ODu 1>1-tx OFF
Simpli:x lirll~Durlex