Thng tin quang

Thng tin quanginh Vn TunKhoa in t - Vin thngH in lc

Gii thiuThi lng: 30 titKim tra: Trc nghim l thuyt + bi tpBT nhm: cc linh kin quang trn tuyn

Ti liu tham khoK thut thng tin quang HVBCVTH thng thng tin quang V Vn San NXB Bu inFiber optic systems John Powers Mc Graw HillFiber optic communication system Govind P.Agrawal Wiley Interscience

Ni dungTng quan h thng thng tin quangCu to si quang & cp quangNguyn l truyn dn nh sng trong si quangSuy hao quangTn sc quangB Pht quangB thu quangBi ton thit k tuyn quang n ginTng quan h thng ttqLch s pht trinS h thng thng tin quangu nhc im ca truyn thng bng si quang

Hy lp c iTh k 21Lch s pht trinLch s pht trin1854: Th nghim John Tyndall 1962: LD bn dn u tin (IBM, Lincoln Lab) 1966: Si quang u tin, suy hao: 1000dB/km (Corning Glass) 1970: Si quang, suy hao: 20dB/km (Corning Glass) 1970: LD hot ng nhit phng 1976: LD bn dn =1,3m v 1,55m 1977: H thng quang thng mi ca s th nht (0,85 m) 1980: H thng quang thng mi ca s th hai (1,3 m) 1982: Si SM, suy hao 0,16 dB/km (~ gii hn l thuyt) 1984: H thng quang thng mi ca s th ba (1,55 m) 1985: H thng WDM 10 knh ~2,5Gb/s (Bell Lab) 1986: EDFA u tin 1988: H thng cp bin u tin vt i Ty Dng v Thi Bnh Dng (565Mb/s) 1989: LD bn dn ph cc hp 1990: Truyn dn soliton 2,5Gb/s khng trm lp 13.000km (Bell Lab) 1992: H thng quang thng mi WDM+EDFA 1995: Cc h thng quang vt i Dng khng trm lp 5Gb/s 1997: Trin khai rng ri cc h thng WDM thng mi 2001: Truyn dn OTDM 1Tb/s qua 70Km (NTT) 2003: 10Tb/s qua 10.000Km

S khi h thng thng tin quangVERY HIGH INFORMATION CARRING CAPACITY.LESS ATTENUATION (order of 0.2 dB/km)SMALL IN DIAMETER AND SIZE & LIGHT WEIGHTLOW COST AS COMPARED TO COPPER (as glass is made from sand..the raw material used to make OF is free.)GREATER SAFETY AND IMMUNE TO EMI & RFI, MOISTUREFLEXIBLE AND EASY TO INSTALL IN TIGHT CONDUITSZERO RESALE VALUE (so theft is less)IS DILECTRIC IN NATURE SO CAN BE LAID IN ELECTICALLY SENSITIVE SURROUNDINGSDIFFICULT TO TAP FIBERS, SO SECURENO CROSS TALK AND DISTURBANCESu im ca thng tin quang

The terminating equipment is still costly as compared to copper equipment.Of is delicate so has to be handled carefully.Last mile is still not totally fiberised due to costly subscriber premises equipment.Communication is not totally in optical domain, so repeated electric optical electrical conversion is needed.Optical fiber splicing is a specialized technique and needs expertly trained manpower.The splicing and testing equipments are very expensive as compared to copper equipments.Hn ch ca thng tin quang

Mng cp quang quc t

Dch v truy nhp fttxng dngVin thng: in thoi, Internet, FTTH, v tuynMng my tnh v cc trung tm d liuTruyn hnh cp: hnh nh, thoi v InternetTin ch: qun l li in v vin thngAn ninh: cm bin hnh nh, xm nhpGii tr: video, audioQuc phng.Si v cp quangCu to si quang

Core Li: ~ 10 um hoc ~50umVt liu thy tinh hoc cht doMang tn hiu nh sng

Cladding Lp bc: 125umVt liu thy tinh hoc cht doCng vi li mang tn hiu nh sng

Primary coating v s cp: 250umCht do tng hpBo v li v bc, nhum mu, to cng cho si

Theo s mode truyn dnn mode Single mode (SM)a mode Multimode (MM)

Phn loi si quang

Theo phn b chit sut li v bcChit sut bc Step Index (SI)Chit sut gim dn Gradual Index (GI)Phn loi si quang

Cu trc tng th cp quangV PE ngoi cngLi cpBng nhm trng nha hai mtV PE ngoi cngBng thp m kmCht in yLi cpCp cng- Phn li: . Phn t gia cng. Cc ng m (khi ng m). Cc si dy ng cp ngun. Cc phn t n & cht in y - Phn v: . V PE th nht bc ngoi li (1mm) . Lp chng m v chng gm nhm . V PE ngoi cng (1,5-2 mm) Cp chnB tr si trong li cp

ng m cht mt si ng m lng mt si

t trong li rnh ch V Khi cc bng dt

Mt s loi cpMt ct ngang cp chn trc tip Cu trc ca cp treo Cu trc ca cp bin

Mt s loi cp

Buffer/jacket colorMeaningYellowsingle-mode optical fiberOrangemulti-mode optical fiberAqua10 gig laser-optimized 50/125 micrometer multi-mode optical fiberGreyoutdated color code for multi-mode optical fiberBlueSometimes used to designate polarization-maintaining optical fiberM mu si nEIA598-A Fiber Color Chart[13]PositionJacket color1Blue2Orange3Green4Brown5Slate6White7Red8Black9Yellow10Violet11Rose12Aqua13Blue with black tracer14Orange with black tracer15Green with black tracer16Brown with black tracer17Slate with black tracer18White with black tracer19Red with black tracer20Black with yellow tracer21Yellow with black tracer22Violet with black tracer23Rose with black tracer24Aqua with black tracerM mu si cpC s vt l v nh sng. nh sng va c bn cht sng va c bn cht ht . Nng lng ca 1 photon: Ep= h.f trong : h - hng s Plank, (= 6,626.10-34J.s = 4,14.10-15eV.s)f - tn s nh sng f = c/o o - bc sng nh sng trong chn khng. nh sng truyn trong mi trng c chit sut n vi vn tc v = c/n.. Trong mi trng ng nht, nh sng truyn thng. Khi gp b mt phn cch gia hai mi trng: mt phn phn x cn mt phn khc x1 Hz1 KHz1 MHz1 GHz1 THzTn s, Hz10010310610910121015101810211 km1 m1 nm1 m1 nm10610310010-310-610-910-12Bc sng, mCc tia XTia cc tmCc tia GammaTia hng ngoinh sngV tuynPht thanhTVC s vt l v nh sng

C s vt l v nh sng3 nh lut v s truyn nh sng1 - nh lut truyn thng:Trong mi trng trong sut v ng tnh, nh sng truyn i theo ng thng2 - nh lut phn x:Tia phn x nm trong mt phng cha tia ti v php tuyn ti im ti, gc phn x bng gc tiC s vt l v nh sng

3 - nh lut khc x:Tia khc x nm trong mt phng cha tia ti v php tuyn ti im ti. Gc khc x v gc ti t l vi nhau theo:n1.sin = n2.sinC s vt l v nh sng

Phn x ton phnGc ti hn C ?????

ng i ca nh sng trong si quang

ng i ca nh sng trong si quang

TE modes (Transverse Electric) no electric field in the direction of propagation.TM modes (Transverse Magnetic) no magnetic field in the direction of propagation.TEM modes (Transverse ElectroMagnetic) neither electric nor magnetic field in the direction of propagation.Hybrid modes nonzero electric and magnetic fields in the direction of propagation.

Mode nh sng trong si quangTip cn theo quang hc lng t, nh sng l mt loi sng in t (hai thnh phn E, H) v truyn dn ca n trong si quang phi tun th cc phng trnh ca nh lut Maxwell. Ngi ta nhn thy rng thnh phn in (vc t E) v thnh phn t (vc t H) ti li v v ca si quang khng c lp vi nhau m c mi lin h thng qua iu kin bin li-bc. Bt c cp nghim no ca h phng trnh Maxwell li v bc tho mn iu kin bin c gi l mt mode truyn sng.

Mode nh sng trong si quangMode sng l mt trng thi truyn n nh ca sng nh sng (cng c th hiu mt mode l mt tia).

Mode nh sng trong si quang

Gc tip nhn

Khu s - naBi tp:q0max = 32,6oD: chnh lch chit sut tng i gia li v bc (%)

S mode truyn dn trong siTn s chun ha tham s V

SIGI

S mode truyn dn trong siGc lan truyn cng nh, bc cng thpMode bc 0 ~ gc lan truyn bng 0o .CC THUC TNH CA si QUANG n mode/ a mode SI/GI Chit sut n1 v n2 Gc ti hn phn x ton phn Khu s NA S mode truyn dn bc modeCh tho lunConnector u ni quangCoupler/adapter u chuyn i quangIsolator dn hng mt chiuCirculator dn hng tun honOptical filter b lc quangGratings cch tEDFA khuch i quang si (pha Erbium)Raman amplifier khuch i RamanSOA khuch i quang bn dnOptical switch chuyn mch quangWavelength converter b chuyn i bc sngOADM b xen r knh quangSplitter b chia quangOptical attenuator suy hao quangOEO Converter b chuyn i quang in quang

Cu to Nguyn tc hot ng ng dngSuy hao trong si quangSuy hao l g?

S suy gim v cng sut hay nng lng ca tn hiu, xy ra cng vi qu trnh truyn i trn knhSuy hao nh hng n iu g?

Cc c tnh mong mun 1 tuyn thng tin:Khong cchTc truynT l li bitSuy hao1 1 11 0 1

Suy hao nh hng n iu g?Khong cch truyn tinT s li bit BERSuy hao quang suy hao A attenuation (W, dB)

Pin v Pout: cng sut tn hiu (W)H s suy hao (dB/km)Pin Pout L (km)

AMP optic fiberCorning optic fiberSuy hao quangSuy hao do hp th

Cc tc nhn hp th tn hiu nh sng trong si quang:Phn t kim loiIon OH-..Suy hao quangSuy hao do tn x

Cc tc nhn gy tn x tn hiu nh sng trong si quang:Chnh lch nng Khim khuyt trn si

Suy hao quangSuy hao do un congCc c ch un cong gy suy hao tn hiu nh sng trong si quang:Un cong v mUn cong vi m

Bn knh cong ti thiu cho si v cp quang

> 5cm i vi si n l

Suy hao quangSuy hao 3dB7.3 km0.5dB/km500 m4.5dB/kmPin = 5mWPout = ? mWBi tp 1Suy hao quang????10 km0.5dB/km500 m1.5dB/kmPin = 5mWPout = 1,2 mWBi tp 2Suy hao quangTn sc trong si quangTn sc l g?Tn sc nh hng n iu g trong truyn dn tn hiu?Cc c ch gy tn sc trong si quangGii php khc phc tn sc trong si quangTn sc quangTn sc quangTn sc l g?

Dispersion = tn sc quangng i ca cc tia sng khi qua lng knh >> lch theo cc hng khc nhauDo u v ri th sao???

Trong si quang, tn sc lm m rng cc xung tn hiu v mt thi gian (gin xung)Tn sc quangTn sc l g?

Tn sc l g?

Tn sc quang tn sc D: gin xung tn hiu v mt thi gian (s)Tn sc nh hng n iu g trong truyn dn tn hiu?Tn sc quang

BERTN SCKim tra 30 pht:

L gii cho s nh hng ca TN SC n cc c tnh ca tuyn truyn dn: khong cch, tc , BERCc c ch gy tn sc trong si quangTn sc quangTn sc quangTn sc mode Modal dispersion

Tn sc quangTn sc mode Modal dispersion

Step IndexGradual IndexSi quang a mode GI c li hn v mt tn sc modeTn sc quangTn sc sc th Chromatic dispersion

Mmat: H s tn sc vt liu (ps/km.nm) Mwg: H s tn sc dn sng (ps/km.nm)

Tn sc quangTn sc phn cc mode Polarization Mode dispersion