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K THUT THNG TIN SI QUANGChuyn : Tm hiu b pht quang iu ch trong h thng quang v kho st cc dng iu ch tn hiu quang bng phn mm m phng Optisystem

Sinh vin thc hin: Nhm 5- Lp D08VT4 1. Nguyn Hi Phong 2. Bi Th Phng Tho 3. L H Thu 4. Ng Quc Tun 5. Nguyn Quang Ton Ging vin hng dn: Ths. Cao Hng Sn

Tm hiu b pht quang iu ch trong h thng quang

MC LCPhn A: Tm hiu b pht quang iu ch trong h thng quang.3 1. B pht tn hiu quang3 1.1. Khi nim b pht tn hiu quang..3 1.2. Cu trc b pht tn hiu quang.3 1.2.1. S khi b pht tn hiu quang3 1.2.2. Cu trc b pht tn hiu quang4 1.3. Phn loi b pht tn hiu quang6 1.4. Ghp ni ngun quang vi si trong mch pht tn hiu quang7 2. B pht tn hiu quang iu ch trc tip9 2.1. Khi nim b pht tn hiu quang iu ch trc tip9 2.2. Mch pht s dng LED...9 2.3. Mch pht s dng LD..9 2.4. u nhc im ca b pht quang iu ch trc tip10 3. B pht tn hiu quang iu ch ngoi..14 3.1. S khi b pht tn hiu ngoi..14 3.2. u im ca k thut iu ch ngoi so vi k thut iu ch trc tip.15 3.3. Phn loi cc b iu ch ngoi s dng hin nay..15 3.3.1. Mach- Zehnder Modulator (MZM)..16 3.3.2. Electroabsorption Modulator (EA)..17 Phn B: Kho st cc dng iu ch tn hiu quang bng phn mm m phng Optisystem...19 1. B pht quang (Optical transmitters)19 2. B pht quang iu bin s dng LED (LED modulation response)20 3. B pht quang iu bin ngoi s dng LD (Semiconductor laser modulation response)22 Danh mc hnh v ...26 Thut ng vit tt.28 Ti liu tham kho...31 Nhm 5- Lp D08VT4 Page 2


PHN A: TM HIU B PHT QUANG IU CH TRONG H THNG QUANG1. B PHT TN HIU QUANG1.1. Khi nim b pht tn hiu quangB pht tn hiu quang l mt trong cc thnh phn quan trng nht ca h thng thng tin si quang. B pht tn hiu quang c chc nng chuyn i tn hiu thng tin u vo dng in thnh tn hiu quang tng ng v ghp vo trong si truyn dn tn hiu.

1.2.

Cu trc b pht tn hiu quang

1.2.1. S khi b pht tn hiu quang

Hnh 1.1. Cu trc b pht quang

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Tm hiu b pht quang iu ch trong h thng quang B iu khin Tn hiu in Tn hiu quang u ra

Ngun quang

B iu ch

B ghp quang

Hnh 1.2. S khi b pht quang 1.2.2. Cu trc b pht tn hiu quang S khi b pht quang in hnh c biu din nh hnh 1.2. Theo , mt b pht quang bao gm: mt ngun quang, b iu ch, b ghp tn hiu quang, mch iu khin cng sut. Tt c cc thnh phn trn c ng gi thnh b pht quang nh hnh 1.3.

Hnh 1.3. B pht quang Ngun quang ca b pht tn hiu quang thng l mt laser bn dn hoc mt it pht quang.

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Tm hiu b pht quang iu ch trong h thng quangTn hiu quang c to ra nh iu ch sng mng quang. C hai phng thc iu ch tn hiu quang, l iu ch trc tip v iu ch ngoi. Ty thuc vo yu cu h thng m phng php iu ch no c s dng. iu ch trc tip thc hin n gin bng cch tc ng trc tip vo dng phn cc ca laser nn hiu qu hn B pht quang v c bn l mt vi gng cho php tp trung tn hiu quang vo mt phng ti ca si quang sao cho c hiu sut ghp sng cao nht. Cng sut ghp quang l mt tham s thit k quan trng. Cng sut ghp quang ln s gip tng khong cch gia cc trm lp/ b khuch i. Tuy nhin cc hiu ng phi tuyn li gii hn ln ca cng sut ny. Cng sut ca tn hiu quang thng c biu din theo n v dBm vi 1 mW c coi l mc tham kho. ( ) ( ( ) )

Nh vy, 1mW tng ng vi 0 dBm, v 1 W tng ng vi -30 dBm. Cng sut ghp quang thng kh nh (< -10 dBm) i vi it pht quang nhng i vi laser bn dn th ln ti ~10 dBm. it pht quang cng b gii hn kh nng iu ch , v th hu ht h thng thng tin si quang s dng Laser bn dn lm ngun quang. Gii hn v tc bit ti cc b pht quang thng do nng lc ca cc mch in t khng p ng c ch khng phi do laser. Vi thit k ph hp, b pht quang cho php iu ch tc bit ln ti 40 Gbps. D liu t ngun pht bn ngoi c a vo b pht quang thng qua n v bin i d liu nh tn hiu xung kch (clock). Ti y d liu c bin i v dng ph hp cung cp cho mch kch thch iu khin dng phn cc cho Laser. Trong trng hp tng qut b pht quang s dng Led cng bao gm cc thnh phn nh hnh 1.2. Tuy nhin nu tn hiu cn pht l tn hiu tng t th mch ch bin tn hiu s n gin hn nhiu. n v bin i d liu (Data conversion Unit) bao gm b gii m tn hiu ng truyn, b bin i song song- ni tip v b sa dng tn hiu. Chc nng ca b bin i d liu l bin i tn hiu in ng vo song song v dng m thng dng NRZ dng ni tip v sa dng tn hiu cung cp cho mch kch thch. Nhm 5- Lp D08VT4 Page 5


Hnh 1.4. S khi n v bin i d liu

1.3.

Phn loi b pht tn hiu quang

Vic iu ch tn hiu quang theo thng tin d liu c th c thc hin nh iu ch trc tip v iu ch ngoi. Do c hai b pht tn hiu quang, l b pht quang iu bin trc tip s dng LED hoc LD v b pht quang iu bin ngoi s dng LD cng vi b iu ch ngoi. iu ch trc tip c thc hin bng cch iu ch thng tin d liu trc tip ln dng nui cho ngun quang nh th ngun quang s pht x nh sng theo thng tin d liu.

Laser Light output Modulator Signal ( electrical)

1010110101 1: light on 0: light off

Hnh 1.5. S khi b pht quang iu ch trc tip Trong trng hp iu ch ngoi th ngun quang pht lin tc nh sng, thng tin c iu ch nh mt b giao thoa k nm bn ngoi.

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Tm hiu b pht quang iu ch trong h thng quang 1010110101 1: light on 0: light off

Laser

Light output

Modulator

Modulator Signal ( electrical)Hnh 1.6. S khi b pht quang iu ch ngoi

1.4. Ghp ni ngun quang vi si trong mch pht tn hiu quangCng sut c ghp vo si cng ln th kh nng truyn dn cng xa. Tuy nhin, li si rt nh nn vic ghp ni ngun v si phi c cc phng php gip kh nng ghp ni c tt hn. trnh c hin tng phn x nh sng ti min ghp ni gia ngun v si quang c th s dng c h s chit sut bng chit sut ca li si. Mt cch khc, u li si quang c th c mi thnh mt thu knh li hng cc tia sng vo li si hoc s dng mt thu knh li ring ti im ghp ni ngun v si quang. Hnh 1.7 m t mt s cch thc ghp ni ngun quang v si cho LED. i vi laser, do ngun sng hp nn c th s dng vi thu knh ghp nh sng thay v s dng ngun thu knh thng thng.

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Hnh 1.7. Mt s cch ghp ni gia ngun v si quang cho LED . i vi LD: S dng vi thu knh: ~ 40 - 90 %

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2. B PHT TN HIU QUANG IU CH TRC TIP2.1. Khi nim b pht tn hiu quang iu ch trc tip

Trong h thng thng tin si quang, b pht quang thc hin pht tn hiu quang mang thng tin t ni pht n ni thu. iu ch tn hiu quang ti b pht phi c mch iu bin cng . Ty vo kiu tn hiu l tng t hay tn hiu s, mch pht iu bin cng phi c nhng c im khc nhau nht nh.

2.2.

Mch pht s dng LED

2.2.1. i vi tn hiu tng t

Hnh 2.1. Mch kch thch s dng LED cho tn hiu tng t i vi tn hiu tng t, mch pht iu bin cng thng s dng transistor lng cc. LED kt ni vi cc gp hoc cc pht thng qua mt in tr hn ch dng. Tn hiu in iu bin c a vo cc gc ca transistor. Gi thit, dng iu bin c dng: ( ) Theo s mch hnh 2.1, dng qua cc gc c dng ( ) ( ) Nhm 5- Lp D08VT4 Page 9

Tm hiu b pht quang iu ch trong h thng quangTrong v . Khi , in p trn LED c dng:

V cng sut quang thu c trn LED s l ( ) Vi l su in bin quang

2.2.2. i vi tn hiu s i vi mch kch thch s dng LED cho tn hiu s khng cn s dng cc in tr phn cc cho transistor lng cc. V tn hiu s, tc sn xung thay i nhanh nn cn s dng thm t C tng tc iu bin

Hnh 2.2.Mch kch thch s dng LED cho tn hiu s

2.3.

Mch pht s dng LD

Khc vi LED, cc mch kch thch cho LD phi s dng mch vng iu khin n nh cng sut do laser rt nhy vi s thay i nhit . Nhit cng tng, th cng sut pht quang ca laser cng gim.

Dng tn hiuNhm 5- Lp D08VT4 Page 10

Tm hiu b pht quang iu ch trong h thng quang Mch iu khin dng kch thch Si quang Mch iu khin dng bm TEC Module LD

Hnh 2.3. M-un laser c h thng n nh nhit Mt mch pht quang iu bin cng c biu din nh hnh 2.4. Mch pht quang ny l s kt hp ca mch iu khin hnh 2.5 v mch iu ch tn hiu hnh 2.6.

Hnh 2.4. Mch pht quang s dng LD in hnh

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Hnh 2.5. Mch kch thch

Hnh 2.6. Mch iu ch tn hiu Nhm 5- Lp D08VT4 Page 12

Tm hiu b pht quang iu ch trong h thng quangHot ng ca mch pht quang iu bin cng c th c phn tch da trn hot ng ca mch iu khin v mch iu ch tn hiu. Mch kch thch c chc nng bin i ngun in p t b bin i d liu v dng dng in cung cp dng phn cc cho laser. Chc nng ny l cn thit v ngun in cung cp cho laser di dng in p hn l dng in. Dng phn cc cho laser c to ra cn phi rt n nh vi dng in ngng c th truyn tn hiu d liu khng b li. Do vy, dng phn cc cn c iu khin bi tn hiu hi tip t cm ng nhit. Trong mch kch thch nh hnh 2.5, in p iu khin, l in p u vo ca opamp. Dng in chy qua in tr R ch ph thuc vo in p u vo m khng ph thuc vo in tr ti, trong trng hp ny l laser diode. Do , bng cch thay i , ngi ta c th iu khin c dng phn cc . Khi nhit thay i, vic n nh cng sut quang u ra ca laser diode c thc hin bi tn hiu hi tip t photodiode PD. PD ny thu nh sng t laser pht ra v to ra dng quang in t l vi cng sut pht quang ca laser. V vy, khi cng sut quang u ra thay i, do s thay i ca nhit , dng quang in s thay i lm cho dng in phn cc cng thay i theo b li nhng thay i trong cng sut quang ca laser. Qu trnh iu ch tn hiu trong mch pht iu bin cng c thc hin bng cch thay i dng in kch thch t mc phn cc n mc cao nht. Mch iu ch tn hiu c biu din trn hnh 2.6. Trong , qu trnh iu ch c iu khin bi dng phn cc qua laser. Chc nng chnh ca mch l cung cp dng in phn cc cc i cho laser. Trong mch iu ch, d liu pht c a vo cc gc transistor , cc B transistor c c nh bi ngun phn cc . Khi tn hiu u vo ln hn , dn, tt, dng qua LD gim lm LD ngng pht sng. Ngc li, khi tn hiu u vo nh hn , tt, dn, dng qua LD tng lm LD pht sng. ng vai tr cung cp ngun dng n nh cho mch vi sai v . kt hp vi mch hi tip dng khuch i thut ton (Op- Amp) n nh dng qua LD di tc ng ca nhit cng nh cung cp tn hiu cho vic gim st Nhm 5- Lp D08VT4 Page 13

Tm hiu b pht quang iu ch trong h thng quangnhit lm vic ca LD phc v cng vic cnh bo v bo dng b pht quang.

2.4.

u nhc im ca b pht quang iu ch trc tip

Trong kiu iu ch trc tip, tn hiu iu ch c thc hin bng cch thay i dng in kch thch chy qua laser. Kiu iu ch ny c gi l iu ch ni hay iu ch trc tip. u im ca kiu iu ch ny l n gin. Tuy nhin, hn ch ca k thut iu ch ny l: Bng thng iu ch ny b gii hn bi tn s dao ng tt dn ca laser diode. Hin tng chirp xy ra i vi tn hiu quang tng rng ph ca xung nh sng. Hin tng ny xy ra i vi laser DFB v v vy l yu t hn ch nghim trng i vi cc h thng truyn dn quang tc cao (ch yu s dng laser DFB lm ngun quang). Hn na, k thut iu ch ny cng khng p dng c trong cc h thng thng tin quang i hi cng sut quang ln ( >30mW) nh cc mng truyn dn c ly xa hay mng truyn hnh cp v vic ch to cc mch pht quang iu ch trc tip hot ng n nh khi iu ch tc cao vi dng in kch thch ln ( >100mA) tr nn phc tp v kh khn hn nhiu. Nhng hn ch trn c th khc phc c khi s dng k thut iu ch ngoi.

3. B PHT TN HIU QUANG IU CH NGOI3.1. S i khi b pht tn hiu quang iu ch ngoi

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Hnh 3.1.S khi b iu ch ngoi S khi b iu ch ngoi c biu din trn hnh 3.1. Theo iu ch tn hiu quang khng thc hin bn trong laser m c thc hin bi mt linh kin quang bn ngoi gi l b iu ch ngoi (external modulator). nh sng do laser pht ra di dng sng lin tc CW.

3.2. u im ca iu ch tn hiu ngoi so vi iu ch tn hiu trc tipVi cu trc ca b iu ch ngoi, k thut iu ch ngoi khc phc c nhng hn ch ca k thut iu ch trc tip: Bng thng hn ch : do b iu ch ngoi quyt nh, v th khng b gii hn bi tn s dao ng tt dn ca laser diode. nh sng laser trong trng hp ny ng vai tr nh sng mang. Khng xy ra hin tng chirp i vi tn hiu quang v laser c kch thch bi dng in n nh nn nh sng pht l sng lin tc c tn s v rng ph n nh. c im ny rt quan trng i vi h thng ghp knh theo bc sng WDM v yu cu v n nh ca bc sng nh sng ti cc knh rt cn thit. Khng b gii hn bi cng sut pht quang v c tnh iu ch do b iu ch ngoi quyt nh.

3.3.

Phn loi b pht quang iu ch ngoi

C hai b iu ch ngoi c s dng hin nay l Mach- Zehnder Modulator (MZM) v Electroabsorption Modulator (EA). Nhm 5- Lp D08VT4 Page 15

Tm hiu b pht quang iu ch trong h thng quang3.3.1. Mach- Zehnder Modulator (MZM) Mach- Zehnder Modulator (MZM) hay cn gi l Lithium niobate (LiNb ) Modulator c ch to bng vt liu Lithium niobate c cu trc Mach Zehnder nh hnh 3.2. Chit sut ca Lithium niobate ph thuc vo in p phn cc. nh sng do laser pht ra khi i vo ng dn sng c chia lm hai phn bng nhau. Khi khng c in p phn cc, c hai na sng nh sng ti khng b dch pha. V vy, ng ra ca b iu ch sng nh sng kt hp c dng ca sng nh sng ban u. Khi c in p phn cc, mt na ca sng ti b dch pha v chit sut ca mt nhnh ng dn sng gim, lm tng vn tc truyn nh sng v lm gim tr. Mt na kia ca sng ti nhnh cn li ca ng dn sng b dch pha v chit sut tng, lm vn tc truyn nh sng gim v lm tng tr. Kt qu l hai na sng nh sng ng ra ca MZM b lch pha v trit tiu ln nhau. Qua ta thy, cng tn hiu nh sng ng ra ca MZM c th c iu khin bng cch hiu chnh in p phn cc. Bng cch ny, bt k dch pha ca sng nh sng ti hai nhnh ca ng dn sng cng c th c hiu chnh.

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Hnh 3.2. Nguyn l hot ng ca b iu ch ngoi MZM a)Khng c in p phn cc b) C in p phn cc iu ch ngoi MZM c s dng ch yu trong mng quang truyn hnh. MZM c mt s hn ch nh sau: suy hao xen cao (ln n 5dB) v in p iu ch tng i cao (ln n 10V). Ngoi ra, s dng MZM cn c mt hn ch na l MZM l mt linh kin quang tch bit. Do MZM c ch to bi LiNb khng phi cht bn dn nn khng th tch hp vi laser DFB trong mt chip. Nhng hn ch ny ca MZM c hn ch bi mt loi iu ch khc l v Electroabsorption Modulator (EA). 3.3.2. Electroabsorption Modulator (EA) B iu ch ngoi EA c cu to l mt ng dn sng lm bng cht bn dn. Khi khng c in p phn cc, nh sng do laser DFB pht ra c truyn qua ng dn sng ny v bc sng ct ca ng dn sng ngn hn so vi bc sng ca nh sng ti. Khi c in p iu ch, rng di cm ca vt liu ng dn sng gim. Hin tng ny c gi l hiu Nhm 5- Lp D08VT4 Page 17

Tm hiu b pht quang iu ch trong h thng quangng Franz- Keldysh v l nguyn l hot ng ca EA. Khi rng di cm gim, bc sng ct s tng ln (do = 1024/ ) v vt liu ng dn sng s hp th sng nh sng ti. V vy, bng cch hiu chnh in p iu ch, c th thay i cc c tnh ca ng dn sng. So vi MZM, EA c nhng u im sau: in p iu ch, khong 2V, nh hn so vi MZM (ln n 10V) C th tch hp vi laser DFB to thnh cc b pht quang c dng chip. Vi nhng u im trn, EA c s dng trong cc h thng WDM.

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PHN B: KHO ST CC DNG IU CH TN HIU QUANG BNG PHN MM M PHNG OPTISYSTEM

1. B pht quang (Optical transmitters)Vai tr ca cc my pht quang l: chuyn i tn hiu in thnh dng quang hc, v khi ng cc tn hiu quang hc kt qu vo si quang hc. Cc my pht quang bao gm cc thnh phn sau: Ngun quang my pht xung in B iu ch quang (xem hnh 1).

Hnh 1 thnh phn b pht Cng sut ghp quang l mt tham s thit k quan trng. Cng sut ghp quang ln s gip tng khong cch gia cc trm lp/ b khuch i. Tuy nhin cc hiu ng phi tuyn li gii hn ln ca cng sut ny. Cng sut ca tn hiu quang thng c biu din theo n v dBm vi 1 mW c coi l mc tham kho.s

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Hnh 2 n v cng sut laser

2. B pht quang iu bin s dng LED (LED modulation response)p ng tn s ca mt n LED c xc nh bi s vn ng sng mang (v do b hn ch bi tui th sng mang n) v in dung k sinh ca LED (c m t bi RC lin tc RC[2]. Nu nh, thin v v pha trc lin tc c p dng, nh hng ca in dung k sinh ca LED c th c b qua. 3-dB LED iu ch bng thng quang hc c nh ngha l tn s iu ch cc chc nng chuyn giao cng sut LED gim 3 dB. Bng thng LED-3dB iu bin quang c th c th hin nh sau: 3dB= /2 /(n+RCn) Chng ti mun chng minh cc tnh cht phn ng iu ch ca n LED. M phng c m t trong hnh sau:

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Cc gi tr mc nh ca tui th sng mang n v RC c nh RC l 1 ns v1 ns, tng ng. Do , 3dB l khong 140 MHz. Tho lun v cc thng s s: v d, bit rate l 300 Mb / s v chiu di chui 128 bit, do , ca s thi gian l khong 430 ns. Mu cho mi bit l 256, do , t l mu l 76 GHz. Do , phn gii mc nh l khong 2 MHz. u tin chng ta gi thi gian truyn Tn v RC c nh Trc, c ngha l 3dB vo khong 140MHz, v phn tch s ng ca s mt nh mt bin php thc hin ca h thng.Kt qu thu c cho 100Mb/s v 300Mb/s truyn c th hin Hnh 2.

Hnh 3 Hiu n ng h thng vi tc bit t ng Nhm 5- Lp D08VT4 Page 21

Tm hiu b pht quang iu ch trong h thng quangR rng hiu sut ca h thng k thut s gim i ng k sau khi tng t l bit trn bng thng Led3-db quang hc iu ch. nh hng ca phn ng iu ch ca Led c th c nghin cu bng cch gi t l bit, v d 300Mb/s ,v lm gim thi gian truyn Tn v RC gi nguyn Trc, do lm tng 3dB. Gi s Tn=TRC 0.5ns,th 3db s vo khong 280MHz Mt ci tin ln trong vic thc hin ca h thng ti 300Mb/s so vi hnh cui. iu ny c minh ha hnh 3

Hnh 4 S ci thin tr ng h thng ti 3 Mb s

3. B pht quang iu bin ngoi s dng LD (Semiconductor laser modulation response)Khi s dng mt tia laser c iu ch trc tip cho h thng truyn ti tc cao, tn s iu ch c th khng ln hn tn s ca cc dao ng th gin.Dao ng th gin ph thuc vo thi gian truyn v c thi gian ca photon.Biu thc gn ng ca s ph thuc ca mnh c cho bi: res=( )

(

)

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Tm hiu b pht quang iu ch trong h thng quangCc tn s dao ng th gin tng vi s thin v laser tc thi. Trong bi hc ny, chng ti s chng minh hiu sut ca h thng tc cao trong khi s dng cc tn s iu ch v tng tn s cng hng (thng qua vic ci thin trong vic thc hin h thng) vi dng thin v laser. M phng c m t trong hnh 1:

Hnh 5 tr

phng

i vi cc thng s mc nh ca m hnh laser phng trnh tc ca chng ti Ith=33.45mA. sp=1ns,ph=3ps, V nu chng ta gi nh iu ch cao im tc thi I=40mA, v IB=40mA tn s cng hng tng ng theo quy nh ca trn phng trnh s l khong 1,3 GHz. Tho lun v cc thng s s: t l bit l 1,3 Gb / s v trnh t chiu di 128 bit, do , cc ca s thi gian khong 98,5 ns. Mu cho mi bit l 512, do , t l mu l 670 GHz. Do , phn gii mc nh l 10 MHz. Trong hnh 6 v hnh 7, nh hng ca tn s iu ch tng ln trn mt trong nhng cng hng v hiu nng h thng s c th hin. Trong hnh 6, 1.3 Gb / Nhm 5- Lp D08VT4 Page 23

Tm hiu b pht quang iu ch trong h thng quangs truyn (10GB / s) c nghin cu. Cc thng s ca cc phng trnh tc tia laser l nhng mc nh (I=IB=40mA) nh m t trc y.

Hnh 6: T ng tn s iu ch trn cng hng R rng, iu ch vi tn s cao hn cc cng hng dn n hiu sut h thng khng th chp nhn c. Trong hnh 7, nh hng ca s thin v tc thi vo tn s cng hng, v do hiu nng h thng, mt t l bit c nh s c th hin. Chng ti s dng 1.3 Gb/s truyn, gi tt c cc thng s khc ging nhau, v s dng IB=20mA

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Hnh

i sai lch t c th i

Nu bn so snh Hnh 7 v Hnh 6 (vi tc truyn 1.3Gb/s v IB=40mA),n l chng minh r rng rng gim ca dng thin v bn di ngng gi tr ca n dn n gim hiu nng h thng. Trong bi hc ny, chng ti cho thy s ph thuc ca hiu sut ca h thng tc cao trn cc tn s iu ch v thin v laser tc thi.

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DANH MC HNH VPhn A: Tm hiu b pht quang iu ch trong h thng quangHnh 1.1. Cu trc b pht quang Hnh 1.2. S khi b pht quang Hnh 1.3. B pht quang Hnh 1.4. S khi n v bin i d liu Hnh 1.5. S khi b pht quang iu ch trc tip Hnh 1.6. S khi b pht quang iu ch ngoi Hnh 1.7. Mt s cch ghp ni gia ngun v si quang cho LED Hnh 1.8. Ghp ni LD vo si s dng vi thu knh Hnh 2.1. Mch kch thch s dng LED cho tn hiu tng t Hnh 2.2.Mch kch thch s dng LED cho tn hiu s Hnh 2.3. M-un laser c h thng n nh nhit Hnh 2.4. Mch pht quang s dng LD in hnh Hnh 2.5. Mch kch thch Hnh 2.6. Mch iu ch tn hiu Hnh 3.1.S khi b iu ch ngoi Hnh 3.2. Nguyn l hot ng ca b iu ch ngoi MZM a)Khng c in p phn cc b) C in p phn cc

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Phn B: Kho st cc dng iu ch tn hiu quang bng phn mm m phng OptisystemHnh 1 thnh phn b pht Hnh 2 n v cng sut laser Hnh 3: Hiu nng h thng vi tc bit tng Hnh 4:S ci thin trong h thng ti 300Mb/s Hnh 5:B tr m phng Hnh 6: Tng tn s iu ch trn cng hng Hnh 7: Gim sai lch tc thi

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THUT NG VIT TTA APD AR ASE B BA BER BH C CW D DBR DCF DFB DR DR DWDM E ELED F FET FPA FPLD FWHM FWM G GI GVD Avalanche Photodiode Antireflection Coating Amplified Spontanous Emission Booster Amplifier Bit Error Rate Burried Heterostructure Continous Wave Distributed Bragg Reflector Dispersion Compensation Fiber Distributed Feedback Dynamic Range Distributed Reflector Dense WDM Edge emitting LED Field Effect Transistor Fabry Perot Amplifier Fabry Perot Laser Diode Full Width at Half Maximum Four Wave Mixing Graded Index Group Velocity Dispersion Diode tch sng quang thc V chng phn x Bc x t pht c khuch i B khuch i cng sut T s li bit Cu trc d th chn Sng lin tc Phn x phn b Bragg Si b tn sc Phn hi phn b Di ng B phn x phn b WDM mt cao LED pht x cnh Transistor hiu ng trng B khuch i Fabry Perot Laser diode c khoang cng hng Fabry Perot rng ton phn ti na ln nht Trn bn sng Ch sGradien Tn sc vn tc nhm Page 28

Nhm 5- Lp D08VT4

Tm hiu b pht quang iu ch trong h thng quangI IM IM DD ISI L LA LD LED M MCVD

Intensity Modulation Intensity Modulation Direct Detection Intersymbol Interference Line Amplifier Laser diode Light Emitting Diode

iu ch cng iu ch cng - Tch sng trc tip Nhiu gia cc k t Khuch i ng truyn Diode laser Diode pht quang Ngng ng hi ha cht bin i Transistor trng bn dn kim loi ng knh trng mode Transistor trng oxit Silic kim loi Ging lng t B iu ch Mach Zehnder Khu s Hnh nh nhiu Schroedinger phi tuyn B khuch i quang B tin khuch i Tn sc mode phn cc Cu trc PIN Nhiu cng tng i Page 29

Modified Chemical Vapor Deposition MESFET Metal Semiconductor Field Effect Transistor Mode Field Diameter MFD MOSFET Metal Oxide Silicon Field Effect Transistor MQW MZ N NA NF NLS O OA P PA PMD PIN R RIN Multiple Quantum Well Mach Zehnder Numerical Aperture Noise Figure Nonlinear Schroedinger Optical Amplifier Pre-Amplifier Polarization Mode Dispersion Positive Intrinsic Negative Relative Intensity Noise

Nhm 5- Lp D08VT4

Tm hiu b pht quang iu ch trong h thng quangRMS RZ S SBS SE SLED SI SMF SNR SPM W WDM Root Mean Square Return Zero Stimulated Brillouin Scattering Spontaneous Emission Surface emitting LED Step Index Single Mode Fiber Signal to Noise Ratio Self Phase Modulation Cn trung bnh bnh phng Tr v 0 Tn x Brillouin kch thch Pht x t pht LED pht x cnh Ch s chit sut phn bc Si quang n mode T s tn hiu trn nhiu T iu ch pha

Wavelength Division Multiplexing Ghp knh theo bc sng

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TI LIU THAM KHO1. Ng Th Thu Trang, Cao Hng Sn, Nguyn Thnh Nam, Bi ging k thut thng tin quang , Hc Vin CNBCVT, 6/2010 2. V Vn San, H thng thng tin quang, NXB Bu in, 2008 3. http://www.e-ptit.edu.vn/hoctap/hoclieu/TTQ1.pdf

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