Dap an Csktttq

8/3/2019 Dap an Csktttq

1/46

I. Si quang

1. Trnh by nhnguimcbncasi quang so vi cp kim loi:

Suy hao truyn dn nh

Bng tn truyn dn ln Khng b nh hng ca nhiu in t

Kch thc nh, trng lng nh, ch to t vt liu c sn, tincy cao

1

n tpK thut thng tin si quang


2/46

I. Si quang

2. Trnh by cuto chung v phn loisi quang

V c cu trc si

M t hnh v

Phn loi si:

- theo chit sut,- theo mode truyn,

- theo vt liu ch to

2


3/46

I. Si quang

3. Nu khi nimvkhuscasi quang v vit cng thckhus

casia mode chitsutbc (MM-SI) v chitsutbini (MM-GI): Trnh by khi nim, gii thch ngha khu s (NA).

+ Khu s NA c xc nh bng sin ca gc nhn nh sngcc i

+ c trng cho kh nng ghp gia ngun quang v si quang Cng thc tnh NAca si a mode chit sut bc (MM-SI) :

Gii thch cc tham s n1, n2

Cng thc tnh NAca si a mode chit sut bin i (MM-GI) :

Gii thch cc tham s n(r), n2

3

2

2

2

1nnNA

22

2

nrnNA


4/46

I. Si quang

4. Vit cng thc tnh s lng mode lan truyn trong si quang a modechit sut bc MM-SI v chit sut bin i MM-GI. S lng mode

truyn trong siphthuc vo cc tham s no cho miloi? Cng thc tnh tham s V: V = 2..a.NA/

S mode ca si SI: M = V2/2

S mode ca si GI: M = V2/4

S mode ph thuc vo cc tham s:- a: ng knh li

- : bc sng nh sng

- NA l khu s ca si quang

4


5/46

I. Si quang

5. Trnh by iukinn mode. Vitbiuthc tnh bc sng ct

iukinn mode: Tnschun ha V casi quang nhhntnsctthnht Vc1 = 2,405

Tnschun ha

Bc sng ct l bc sng ngnnhtsi quang lm vic trong

vng n mode

Biuthc:

5

NAaV ..2

NAa

Vcc

.2


6/46

I. Si quang

6. Nu khi nimv mode nh sng, phn loi mode nh sng.

- Khi nim mode:

+ Nghim ring ca h phng trnh Maxwell trong iu kin

bin xc nh

+ Biu din dng phn b in t trng khng i lan truyn

trong li si

- Phn loi: Mode truyn dn, mode pht x, mode d

6


7/46

I. Si quang

7. Nu khi nimv suy hao casi quang. Vitbiu thc tnh hs suyhao.

Suy hao l s suy gim cng sut nh sng khi lan truyn qua si

quang

Hnh v cho php tnh suy hao

Biu thc: Pin = Poutexp(-L)

H s suy hao:

7

)

P

Plog(

L

10)km/dB(

out

in


8/46

I. Si quang

8. Nu khi nimv tn sc trong si quang. Cho bit nghacanvhstn sc.

Tn sc l hin tng lm gin rng xung nh sng khi lan truyn qua

si quang

n v h s tn sc: D(ps/km.nm)

ngha: Cho bit gin rng xung nh sng khi ngun quang c rng ph xc nh truyn qua mt di si xc nh.

8


9/46

I. Si quang

9. Trnh by cimvhs tn sccasi quang dch tn sc DSF, siquang b tn sc DCF v si quang tn scphng.

Cc si quang ny c phn b chit sut khc nhau c im tn

sc khc nhau

Si dch tn sc: c tn sc nh nht ti ca s bc sng 1550nm

Si b tn sc: c h s tn sc m

Si tn sc phng: c h s tn sc xp x 0 ti mt vng bc sng

9


10/46

I. Si quang

10. So visin mode, hs suy hao v hs tn sccasia mode ckhc bit g.

V suy hao:

+ Suy haosia modelnhn suy haosin mode

+ Nguyn nhn: do kchthcsia modelnhn kchthcsi

n mode

V tn sc:

+ Tnscsia modelnhn tnscsin mode

+ Nguyn nhn: dosia mode c thm thnhphn tnscmode

10


11/46

I. Si quang

11a. Trnh by cu to v nguyn l truyn nh sng trong sia mode chitsutbc (MM-SI) theo phng php quang hnh.

Cu to si MM-SI:

+ Hnh v mt ct chit sut

+ Kchthc2.a50m; d125m

+ Chitsutli vv: n1 khngi, n2khngi, n2< n1S lan truynca nh sng trong si:

+ Hnhvslantruyn cc tia sng

+ Tia sng lantruyn cdngccnggp khc dophnx ton

phn.+ Truyna mode, tnscln, do chnhlchthigian lantruyn

gia cc mode.

11


12/46

I. Si quang

11b. Trnh by cu to v nguyn l truyn nh sng trong sia mode chitsutbini (MM-GI) theo phng php quang hnh.

Cutosi MM-GI:

+ Hnhvmtctchitsut

+ Kchthc2.a50m; d125m

+ Chit sut li v v: n1thay i n1=n(r) , n2khng i, n2< n1

S lan truyn ca nh sng trong si:

+ Hnh v s lan truyn cc tia sng

+ Tia sng lan truyn c dng ng cong

+ Truyn a mode, tn sc nh hn tn sc si MM-SI.

12


13/46

I. Si quang

12. Hy tnh tn sc mode casia mode chitsutbcda theo nguyn ltruyn nh sng trong si theo phng php quang hnh.

S lan truynca nh sng trong si MM-SI:

+ Hnhvslantruyn cc tia sng

+ Xcnhctia c qungngtruynngnnht:truyndc

theotrcsi+ Xcnhctia c qungngtruyn dinht:tngngvitia

c gc vousibngNA

Tnh tn sc mode

+ Vit biu thc thi gian truyn ca tia ngn nht

+ Vit biu thc thi gian truyn ca tia di nht

+ Tn sc mode bng hiu thi gian truyn

13


14/46

I. Si quang

13. Trnh by cc nguyn nhn gy ra suy hao v vc tnh suy hao casin mode tiu chun

Khi nim suy hao trong si quang:Khi nh snglan truyn trong si quang, cng sut nh sng gim dn.

Cc nguyn nhn gy ra suy hao:

+ Suy hao do hp th

- Suy hao do vt liu ch to si quang (SiO2) hp th nh sng.

- Suy hao do tp cht: ion kim loi (Fe+, Cu+) v ion OH-

- Suy hao do hp th IF, hp thu UV

+ Suy hao do tn x

- Tn x Rayleigh: do cc khim khuyt rt nh trong qu trnhch to.

- Suy hao do ng knh li thay i, do un cong

V c tuyn suy hao si

+ Hnh v

+ Ch thch y

14


15/46

I. Si quang

14. Trnh by cc loi tn sc trong si quang n mode v nu nhhngcatn sc.

Khi nim tn sc trong si quang:Khi nh sng lantruyn trongsiquang, rngxung nh sng thayi.

Cc loi tn sc trong sin mode:

+ Tnscvtliu: dochitsutlisiquangphthucbcsng n= n() m nh sngngun quang pht ra baogmnhiubcsang

dnnthigian lantruynca ccbcsngs khc nhaugyra tnsc.

+ Tnscngdn sng: do nh sng lantruyn trongc li vvsiquang. Thnhphn lantruyn ngoivinhanhhn.nhhngchyu trongsiSM.

+ Tnscmode phncc

Hnh vc tnh tn scsin mode

nhhngca tn sc:

+ Gy ranhiu ISI

+Giihntc bittruyn trnsi

15


16/46

II. Mt s vn vt l c bn

1. Khi nimcht bn dn. Nu s khc nhau ca bn dn loi p v bn dnloi n.

Cht bn dn:

+ L vt liu c th dn in mt iu kin no nhng iu

kin khc li l cht cch in (v d theo nhit )

+ Cc vng nng lng: vng ha tr, vng dn, di cm Bn dn loi p: nng l trng nhiu hn nng in t

Bn dn loi n: nng l trng t hn nng in t

16


17/46


2. Trnh by qu trnh phn ccthun v phn ccngc cho tip gip p-n.

Khi cha phn cc

+ Hnh v tip gip p - n

+ Qu trnh dch chuyn ca in t v l trng

Khi phn cc thun

+ Hnh v tip gip p-n, dng ngun ni vi p, m ngun ni vi n+ S xut hin ca in trng ngoi

Khi phn cc ngc

+ Hnh v tip gip p-n, m ngun ni vi p, dng ngun ni vi n

+ S xut hin ca in trng ngoi

17


18/46


3. Tnh tn s nh sng v nng lng photon tng ng vi bc sng1310nm. Cho bit hng s Plank h=6,625.10-34 J.s v vn tc nh sng

trong chn khng c=3.108

m/s. Tnh tn s nh sng: f = c/(chuyn v cng n v)

Tnh nng lng photon: E = h.f

18


19/46


4. Trnh by khi nimvcu trc dth,cu trc dth kp.

Cu trc d th:

+ Hnh v tip gip p - n

+ Nng lng di cm ca bn dn p v bn dn n khc nhau

Cu trc d th kp

+ Hnh v cu trc d th kp+ Cu trc d th kp gm hai cu trc d th lin tip

19


20/46


5. Gii thch hintngomtxuthin trong qu trnh pht xca LD

- t mt in th phn cc thun (c chiu dng in hng t lp psang lp n).

- Khi , cc in t t lp n b ko v cc dng v chuyn di vo vnghot cht, trong khi cc l trng lp p b ko v cc m v cng

chuyn di vo vng hot cht.- Cc in t v l trng chuyn di vo vng hot cht b giam trong lp

hot cht ny v do hng ro d th. T to nn o ln mt .

20


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6. Hy gii thch cc qu trnh hpth v pht x nh sng (pht xt pht v pht x kchthch). Cho bitth no l nh sng kthp v nh sng khng kthp.

Qu trnh hp th nh sng:

+ V hnh m t qu trnh hp th+ in t mc nng lng thp E1c kch thch bi mt ngun nng lng (v d

in nng, nhit nng, ) nhy ln mc nng lng cao hn E2

Qu trnh pht x t pht:+ V hnh m t qu trnh pht x t pht

+ in t mc nng lng cao E2sau mt thi gian tn ti s nhy v mc nnglng thp hn E1, pht ra photon nh sng c nng lng bng E2 E1, c pha vhng ngu nhin

Qu trnh pht x kch thch:+ V hnh m t qu trnh pht kch thch+ Photon nh sng kch thch mt in t ang mc nng lng cao E2lm cho in

t nhy v mc nng lng thp hn E1, pht ra photon nh sng th cp c cngpha, cng tn s vi nh sng kch thch.

Gii thch nh sng kt hp, nh sng khng kt hp

+ nh sng khng kt hp: trong qu trnh pht x t pht nh sng pht ra ngu nhin(khng c quan h v pha gia cc photon, v hng pht x l ngu nhin).

+ nh sng kt hp: trong qu trnh pht x kch thch photon nh sng th cp pht ra

c cng tn s, cng phn cc v hng truyn vi phng truyn sng. 21


22/46


7. Trnh by nguyn l pht x nh sng catip gip p-n.

Vc hnh m t qu trnh pht x nh sng v ch thch y

Nguyn l pht x nh sng:

+ Khichacpngun phncc:

+ Khi c in trng ngoi tc ng, cc in t dch chuyn t bndn n sang p v ngc li l trng dch chuyn t p sang n.

Trong qu trnh dch chuyn, l trng v in t ti hp vi nhau vgii phng ranng lng nh sng di dng sng in t

+ Photon nh sng cbcsng:BX = h.c. / (Ec Ev)

22


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8. Trnh by nguyn l chuyni quang incatip gip p-n.

V c hnh m t qu trnh chuyn i quang in v ch thch y

Nguyn l chuyn i quang in:

+ Khi cha c nh sng chiu vo: c dng ti

+ Khi c nh sngchiu vo: photonbhpth sinh racpltrng-int,ditcngcaintrngngoiintchuynngvpha n vltrngchuynngv pha pto thnh dngin trongmch.

+ Kch thc vng ngho nh nn hiu sut chuyn i O/E thp.

23


24/46

III. Pht quang

1. Trnh by cc c tnh v tham s c bn ca LED.

Cng sut nh sng bc x Cc tch cht nh sng

c tuyn tnh pht x nh sng

24


25/46

Cng sut nh sng bcxca LED

Cng sut nh sng bc x ca LED c xc nh theo cng thc:

l dccactuyn tnh P I ca LED tiimcng tc (P0P, I0P) ca LED (s trnh byni dungsau). Trong thct, HP-LED = 1- 50 w/mA.

)(.)( 0 tiHPtP DLEDPPLEDP

DIDID

LEDPLEDP

dI

dPH

0

Trong :

iD(t) l dng in iu khin (tn hiu truyn dn) LED

1. Trnh by cc c tnh v tham s c bn ca LED (tip theo)


26/46

Cc tch cht nh sng ca LED

Phn b ph nh sngca LED c m tbi hnh sau:

Ph cng sut nh sng bcxca LED

0

PoP

Phn b hnh hc nh sng bcxca LED

Phn b hnh hc cng nh sng pht x ca LED pht x mt (a) v LEDpht x cnh(b)

Si

quang

LED

pht x

mtab

LED pht

xcnh

Si

quang



27/46

ctuyntnh pht x nh sng ca LED

c tuyn tnh pht x nh sng ca LED l mi quan hgia cng sutnh sng pht x v dng iukhinca LED.

Hnh 3.23.ctuyntnh pht x nh sngca LED

IBh-LED

P

O I

Gii thch ctuyn P-I ca LED:

I = 0 => P = 0

I 0 => P > 0 :

- I tng v < IBh-LED => P tngtuyn tnhvistngca I,

- I = IBh-LED => P t gi trcci =>S pht xtrng thi bo ho,

- I tng v > IBh-LED => P gim vistngca I.



28/46

III. Pht quang

2. Trnh by cc c tnh v tham s c bn ca Laser.

28

Cng sut nh sng bc x :

Cc tch cht nh sng:

c tuyn tnh pht x nh sng:


29/46

III. Pht quang

3. V s v trnh by nguyn l ca mch pht dng LED vi tn hiu avo iu ch l tn hiu tng t.

V c s mch, ch thch y cc linh kin trn mch

Gii thch chc nng cc phn t: R1, R2: lm nhim v phn p, R3lm nhim v n nhit

Trnh by nguyn l hot ng:+ Transistor lm vic ch khuch i

+ Hot ng ca LED tt, sng theo tn hiu u vo

V dng sng tn hiu vo, ra theo c tuyn pht x

29


30/46

III. Pht quang

4. V s v trnh by nguyn l ca mch pht dng LED vi tn hiu avo iu ch l tn hiu s.

V c s mch, ch thch y cc linh kin trn mch

Gii thch chc nng cc phn t: R1, R2: lm nhim v phn p, R3lm nhim v n nhit

Gii thch chc nng ca mch tng tc RC Trnh by nguyn l hot ng:

+ Transistor lm vic ch thng, tt

+ Khi tn hiu u vo l bit 1

+ Khi tn hiu u vo l bit 0

30


31/46

III. Pht quang5. V cu trc v cho bit nguyn l hot ng ca Laser phn x Bragg phn tn

(DBR)

31

- V v ch thch ccu trc ca Laser DBR

- Ch r v tr t cch t Bragg, chu k cch tu

- Trnh by nguyn l hotng:

+ nh sngcto ra trong vng tchcc

+ Cchtphnx phn tn Bragg cchiu dingnngvai trbphnxchnlclctns thayth chobungcnghngFabry-Perot.

+ Cu trc cch t nm hai bn vng hot tnh c tc dng nhhai gngphnxviccbcsngBtho mniukinphnx.

B

effn22m2

+ C nhiu mode trong vng hot tnh nhng ch c mt bc sng cphn x tr li v c khuch i. Cc mode dc gn vi bc sngBs b suy gim do suy hao.


32/46

III. Pht quang

6. V cu trc v cho bit nguyn l hot ng ca Laser phn hi phn tn

(DFB)

32

- V v ch thch ccu trc ca Laser DFB

- Ch r v tr t cch t Bragg, chu k cch tu


+ nh sngcto ra trong vng tchcc

+ DFBsdnghintngphnx Bragg nn cc mode bn vchnlctns

+ Sng quang lantruyn song songvicch t. giao thoaxyra th saumtchukcchtphaca sng thayi2m (m nguyngilbcccht)

B

effn22m2

+ Nu iu kin trn khng tho mn th nh sng tn x t cch t s trittiu ln nhau. Vi m=1 thBgi l bc sng Bragg bc 1: B= 2neff


33/46

III. Pht quang7. V s khi mch pht dng Laser c n nh nhit v n nh cng sut,

trnh by hot ng ca mch.

33

- Vngskhi

- Nu ch thch y- Nguyn l chuyn tn hiuu vo thnh tn hiu quang:+ Tnhiuca quamchkhuchiAGCricngvidng thin pa voiu

ch LD+ Cngsutnh sng LD pht raphn lncghp vosiquang, mtphnnhati

PD gim st cngsutpht.

- Nguyn l nnh cng sut

+ PDchuyn cngsutnh sngnhnctLD thnh dng tch quang.+Nu cngsutpht thayi (lnhocnhhn gi trdanhnh) th dng tch quangs

thayi.+Sthayica dng tch quangscatrliiuchnhmch thin p vmch

AGCnnh cngsutpht.

- Nguyn l nnhnhit:

+ Khinhit LD thayis lmin trnhitgn trong LD thayi,dnn gi trdngin gim stnhitavmchnnhnhitthayi.

+ LDcgn trnbphn lm mt Peltier, mchnnhnhtsiukhin thayinhitcabphn Peltierdnnnnhcnhit cho LD.


34/46

III. Pht quang8. Trnh by cu to v nguyn l pht quang ca LED cu trc d th kp.

34

- V v ch thch ycu trc ca LED

- V phn bnnglng v chitsuttngngvicu trc LED- M tcu trc dth kp:

+Gm cclp bndn crngdicm khc nhau

+ Gip giam hmint,ltrngv photon trong vng tchcc.


+ Khicha cin p phnccthun:+tin p phnccthun ln LED:

Khi, ccin t t lp nbkovccdngvchuyndivo vnghotcht, trong khi cc ltrng lp pbkovccm v cngchuyndivovnghotcht.

Ccintvltrngchuyndivo vnghotchtbgiam tronglphotcht

ny v do hng rodth. Tto nnolnmt.Ccintvltrngbgiam trong vimtrtcao tihptnhinvinhaupht ra nh sngtnhin (a/s khngkthp).

Trn cs tihp, ccin tv l trng trong lphotchtpht ra nh sng tnhin. Qu trnh phtxgil phtxtnhin.


35/46

III. Pht quang

9. V cu trc v trnh by nguyn l hot ng ca Laser bn dn c

khoang cng hng Fabry-Perot

35

- Vcu trc laser c khoang cnghng Fabry-Perot, ch thch y

- Nguyn l hotng:


36/46

- Hp th photon v pht x kch thch

Khi nh sng pht ra trong qu trnh tr v trng thi E1 vi nng lng E2- E1 tip tc kchthch mt in t khc ang trng thi kch thch.

in t ny hp th nng lng nh sng ti v trong qu trnh tr v trng thi E1 n s giiphng ra mt nng lng nh sng di dng sng in t vi ln ln hn nhiu ln E2- E1(nng lng pht x t pht).

chnh l qu trnh pht x kch thch hay pht x cng bc v nh sng c gii phng ratrong trng hp ny l nh sng pht x kch thch.

- Ti hp v pht x t pht:

Cc in t v l trng b giam trong lp hot cht vi mt rt cao ti hp t nhin vinhau v pht ra nh sng t nhin.

- To nh sng kt hpNh b cng hng quang, nn cc sng nh sng pht x kch thch ca Laser ng pha vinhau theo mt phng thng ng vi phng truyn sng ca chng. nh sng pht x ratrong trng hp ny l nh sng kt hp khng gian.

ng thi, nh sng pht x kch thch ca Laser cn lin tc c bc sng n. nh sng phtx ra trong trng hp ny l nh sng kt hp thi gian.

- Nguyn l hot ng ca Laser bn dn c khoang cng hng Fabry-Perot

9. V cu trc v trnh by nguyn l hot ng ca Laser bn dn c khoang cng

hng Fabry-Perot (tip)


37/46

III. Pht quang

10. V s khi c bn ca b pht quang v cho bit chc nng cc khi.

37

- Vcskhica my pht quang

- Chcnngngun quang: chuyni E/O

- Chcnngbiukhin (kch thch)

- Chcnngbiuch

- Chcnngb ghp quang


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IV. Thu quang

1. Trnh by cu to v nguyn l tch sng quang ca photodiode PIN.

38

- V v ch thch ycu trc ca PIN

- V phn btrngtngngvicu trc PIN

- M tcu trc dth kp:


+ Khicha cin p phncc

+tin p phnccngcln PIN

+ Khicha c nh sngchiu vo: trongmch c dngti

+ Khi c nh sngchiu vo: photon nh sngbhpthto thnhcpint-ltrng

+ Cccpin t - l trng to ra trong lp p v nhunhkhng tham gia todngin

+ Cccpint-ltrngto ra trong vng nghoditcdngcaintrngngoichuynngramch ngoito thnh dng tch quang

IV Th


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IV. Thu quang2. Trnh by cu to v nguyn l tch sng quang ca photodiode thc APD

39

- V v ch thch ycu trc ca APD

- V phn btrngtngngvicu trc APD- M tcu trc:

+ Thmmtlp bndn pto vng thc, tp trungintrngln.


+ Khicha cin p phncc+tin p phnccngcln APD

+ Khicha c nh sngchiu vo: trongmch c dngti

+ Khi c nh sngchiu vo: photon nh sngbhp th to thnhcpin t - ltrng

+ Cccpin t - l trng to ra trong vng nghodi tc dngcain trngngoichuynngramch ngoito thnh dng tch quang

+ Nguyn lkhuchi: int,ltrngcto ra khiiquatip gip p-n+scgiatc, khi chng cngnngln chngs vapvicc nguyntvto racccpint,ltrngmi

+HskhuchiM


40/46

IV. Thu quang

3. Trnh by cc tham s c tnh ca photodiode PIN

40

- Dng photo ca PIN - Photodiode

- Dng ra ca PIN - Photodiode

- ctuyntnhca PIN - Photodiode

-Nhiu

trong PIN

Photodiode: trnhby

nguyn nhnca

ccloi

nhiu)

+ Nhiu dng in ti,

+ Nhiu dng d,

+ Nhiu nhit,

+ Nhiu lng t tn hiu.


41/46

IV. Thu quang

4. Trnh by cc tham s c tnh ca APD

41

- Dng photo ca APD

- Dng ra ca APD

- ctuyntnhca APD

- Nhiu trong APD: trnh by nguyn nhn ca cc loinhiu)

+ Nhiu dng in ti,

+ Nhiu dng d,

+ Nhiu nhit,

+ Nhiu lng t tn hiu,

+ Nhiu do hiu ng quang thc.


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IV. Thu quang5. Trnh by cc loi nhiu trong b thu quang.

42

- Nhiu trong APD: trnh by nguyn nhn v cng sutca cc loinhiu)

- Nhiu trong PIN Photodiode: trnh by nguyn nhn v cng sutca

cc loinhiu)

+ Nhiu dng in ti,

+ Nhiu dng d,

+ Nhiu nhit,

+ Nhiu lng t tn hiu.

+ Nhiu dng in ti,

+ Nhiu dng d,

+ Nhiu nhit,

+ Nhiu lng t tn hiu,

+ Nhiu do hiu ng quang thc.


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IV. Thu quang6. Trnh by cc tham s nh gi tn hiu ti my thu quang.

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- Ts tn hiu trn nhiu quang: OSNR

+nhngha SNR

+nhngha OSNR: SNR trongmin quang

+ Cch xcnh OSNR

+Biuthc:

OSNR(dB/B-nm)=10log [(S+N)/N 1]

- Tsli bit: BER

+nhngha

+ Cngthctnh, giithch cc thams(iviPIN, APD)

+ BERphthucvo cngsutthu vhiusutlngt

+ BERphthucvo ccloinhiu:nhiulngt,nhiu dngti,nhiu do nh sngnn,

nhiunhit- Hsbini quang-in:

+nhngha: l thamsbiuthchoctnhchuynicab tch quang(obngdngtch quang trnmtnvcngsutquangti)

+Biuthc

hc

eH


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III. Pht quang

11. V s khi c bn ca b thu quang v cho bit chc nng cc khi.

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- V s khi c bn ca b thu quang analog v cho bit chcnng cc khi.

- V s khi c bn ca b thu quang digital v cho bit chc

nng cc khi.


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V. Thit k h thng

1. V hnh v cho bit nguyn l khuchicatrmlp quang in.

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- V s khi c bn ca trm lp quang analog v cho bit chcnng cc khi.

- V s khi c bn ca trm lp quang digital v cho bit chc

nng cc khi.


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V. Thit k h thng

2. H thng thng tin quang n knh hotng tc bit 10Gbps, mNRZ 50% sdngngun pht quang n mode bc sng 1550 nmvirngph 1nm truyn trn sin mode tiu chun SMF c hstn sc D=0,26 ps/nm.km. Hy tnh khong cch tia m tibtuxy ra hintng xuyn nhiugia cc tn hiu ISI.

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- Tnh crng xung tn hiu

T=0.5(1/Rb)

- Xc nhc gin rng xung tia cho php bngT

- Xc nhckhong cch tia

L=T/(D.)

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