TTQ. Nhóm 4 - ban nho

7/31/2019 TTQ. Nhm 4 - ban nho

1/18

Thng tin quang 2 Thit k tuyn thng tin quang

NI DUNG BO CO

1. Bi ton.................................................................................................................2. Yu cu..................................................................................................................

3. Phng n thit k................................................................................................

4.Thit k mng DWDM.........................................................................................

4.1.Thit k pha pht:..........................................................................................

4.2.Thit k b thu quang:....................................................................................

4.3 Thit k mi trng truyn dn:.....................................................................

4.4 Thit k si b tn sc:..................................................................................

4.5 .Thit lp thng s ton cc...........................................................................5. Kt qu m phng

PTIT - H10VT5 1 Nhm 11


2/18


1. Bi ton.

Xy dng phng n thit khthng thng tin quang WDM c sdng khuch i

quang EDFA, vi cc yu cu thit k nh sau:

Tc bit: 10 Gbit/s

C ly truyn dn 600Km S lng knh bc sng: 4 knh

2. Yu cu

b. S dng phn mm Optisystem xy dng m hnh m phng h thng thng tin quang

WDM theo phng n thit k.

Lu : cc tham s ton cc (global parameters m phng) c thit lp nh sau

Tc bit: 10 Gbit/s

Chiu di chui: 128 bits

S mu trong 1 bit: 64

b. a cc thit b o vo m hnh m phng. Cc thit b o trn tuyn c t ti cc v

tr ph hp xc nh c cht lng tn hiu ti cc im cn thit trn tuyn. Cc thit

b o c bn:

- Thit b o cng sut quang

- Thit b phn tch ph quang

- Thit b o BERd. Hin th kt qu m phng bng cc thit b o t trn tuyn

e. Thay i cc tham s ca cc phn t trn tuyn t c BER = 10 -12

3. Phng n thit k

Loi si: Si quang dch tn sc khc khng (G.655)

Ngun pht: -Loi ngun: Laser.

-Phng thc iu ch: iu ch ngoi

B thu: S dng PIN kt hp vi b lc thng thp Bessel

4.Thit k mng DWDM

4.1.Thit k pha pht:

Ngun pht quang lazer CW lazer

B pht xung NRZ pulse genarator



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B pht bt in pseudom-Radom Bit sequence Genarator, iu ch Mach-zehnder

Modulator.

Do h thng WDM ghp 4 knh tn hiu nn pha u pht s bao gm c 4 b pht.

Thit b c xp xp nh trn c gi l phng php iu ch ngoi.

Do ghp 4 knh tn hiu nn b WDM Mux s dng l Mux 4x1

4.2.Thit k b thu quang:

- B tch knh Demux 1x4

- PIN kt hp b lc thng thp Bessel

Ngoi ra quan st cht lng tn hiu u thu cn c thit b o Ber, genarator 3R

c t v tr thch hp.



4/18


4.3 Thit k mi trng truyn dn:

Do mi trng truyn dn s dng si quang G655 ( si quang dch tn sc khc khng)

nh vy cn phi thit k si quang G655 vi cc thng s c trng.

Truy nhp th vin : Defaults-> optical fibers library-> optical fibers. Kch p vo si

cp v thay i cc thng s ca si.Khi kch p vo si quang th xut hin bng:

Mc Main

Label : cho php ta thay i tn ca si qung (t l G655).

Length : cho php thay i chiu di ca si quang.

Attenuation: cho php thay i suy hao si quang : vi si ny ti ca s 1550 c

suy hao l 0.35dB/km.

Mc Disp cho thay i gi tr ca tn sc v dc tn sc .

Dispersion: Nhp gi tr 6 ps/nm/km

Dispersion Slope: Nhp gi tr dc tn sc chn gi tr 0.09 ( hoc 0.07, 0.05 ty

ta dng si dch tn sc no) ps/nm2/km.

Thng th ta chn gi tr l 0.09ps/nm2/km.

Mc PMD h s tn sc mode phn cc c gi tr ln nht l 0.1ps/km1/2



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Nhp gi tr ny v tch vo mc Disp, kt thc bng OK.

Ta i tnh chiu di cc i ca tng chng theo phng php tinh thi gian

tng ca xung

Ta c thi gian tng sn xung ca laser diode l t LD = 0,1ns

Thi gian tng sn xung ca diode tch quang l tPS = 0,2nsSTM 4= 622,08 Mb/s = 0.62208 Mb/s

Si G655 s dng m NRZ

tNRZ = 0,7/ 0,62208 = 1,125 ns

Gi s chn Lmax = 60km.

ttb = D = D * Lmax *

( Theo bi ra s dng si G655 hot ng ti = 1550nm c h s tn sc tng

D = 20 ps/(nm.km)

Suy ra ttb = 20 ps/(nm.km) * 60km * 1nm = 1200 ps = 1,2 ns

tht = (t2LD + t2PS + t2tb) = ( 0,12 + 0.22 + 1.22) = 1,22 ns

Suy ra tht > tNRZ khng tha mn

Chn Lmax = 50km khi ttb = 20 ps/(nm.km) * 50km * 1nm = 1000 ps = 1ns

tht = (t2LD + t2PS + t2tb) = ( 0,12 + 0.22 + 1 2) = 1,014 ns

tht < tNRZ tha mn

Vy chiu di cc i l Lmax = 50km.

Thit k si b tn sc:Do si G655 c tn sc nh nn vic gim tn sc c thc hin bng si b tn

sc DCF.

Theo tnh ton tnh cht ca si b tn sc ta thy c 1km si DCF c th b tn sc

cho 5km si SMF. Vy vi si c Lmax = 50km suy ra chn si DCF c chiu di l 50/5 =

10km.

+ Tnh ton thng s ca si b tn sc:

Si G655 c chiu di l L1= 50km.

tn sc l : D1= 4.4 ps/nm.km.

dc tn sc : 0.05ps/nm^2.km.

Chiu di si b tn sc ( DCF) l L2 =10km

Th b tn sc D2= -D1L1/L2.= -704.4/10=-30.8 ps/nm.km.

dc tn sc : 0.075ps/nm^2.km.



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Do khong cch ng truyn ln thun tin cho vic m phng chng ta s

dng b Sloop ng vai tr nh mt b nhn cc vng lp.

Vic thay i gi tr Loop cho php ta thay i s vng lp ty theo chiu di ca

si s dng, v nu nh h thng truyn tc cao c s suy hao tn sc th cn dng thm

b b tn sc DCF hp l. Vi c ly truyn dn l 600km: Nu ta chn Si G655 di50Km, si DCF di 10km th ta s Loop= 600/(50 + 10)=10 ln. Vic thay i Loop cng

c thc hin bi vic kch p Loop control v thay i thng s, kt thc bng

OK.

+ Khuch i tn hiu (EDFA): Defaults-> Amplifiers otipcal-> EDFA ->

Optical Amplifier.

Do tn hiu c truyn trn si quang vi c ly truyn dn di , nn gy ra suy hao siquang, v suy gim cng sut pht tn hiu. khc phc hin tng suy gim cng sut v

suy hao tn hin i vi h thng WDM s dng b khuc i EDFA. Vi h s khuch i

G ng bng lng suy hao trn tuyn.

Trong h thng G=

4.4 M hnh m phng ton h thng



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4.5 .Thit lp thng s ton cc

Cc tham s ton cc bao gm c:

Tc bt ( bt rate)= 10Gbit/s Chiu di chui bt (Bt Sequence length)= 128 bt.

S lng mu trn mi bt ( Number of samples per bit)= 64.

Cc thng s ton cc ny s nh hng ti tt c cc thnh phn trong thit k c s

dng. Cc tham s trn c s dng tnh ton :

Ca s thi gian (Time Window)= chiu di chui bt 1/ tc bt= -> ca s thi

gian = 1281/ 10000000000= 12.810-9(s).

S lng mu (Number of samples)= chiu di chui bt* s mu trn mt bt

S lng mu = 12864=8192.

Tc ly mu (sample rate)= s lng mu / ca s thi gian.

Tc ly mu = 8192/ 12.810^-9=640000000000(Hz).

Cch Thit lp thng s ton cc

- thit lp thng s ton cc thc hin nh sau:

Cch 1: kch p vo mn hnh Layout.

Cch 2:Layout -> Parameters t cng c Menu.

Khi mn hnh parameters xut hin:



8/18


Thay i cc thng s ca cc phn t trong d n

Thc hin kch p vo phn t cn thay i tham s -> hp thoi v cc tham s

ca phn t xut hin .

Di chuyn con tr n cc gi tr thch hp.

Tin hnh nhp gi tr cn thay i.

Quan tm ti ba ch ca tham s l Norman, Script v Sweep:

+ Trong ch Scrip c thc hin khi tham s ny l tham s ton cc, n c lin

quan n tt c cc phn t khc trong h thng.+ Ch Sweep c s dng khi thc hin qut tham s.



9/18


H thng s dng c bng tn:f= 100 Ghz.

Bc sng trung tm s dng: =1552.52 nm.

Vn tc nh sng : C=3*10 8m/s.

Khong cch cc bc sng: =( f2 )/ C= 0.8nm.

Gi s chn frequency ca CW lazer = 1552 nm.

Th cc knh tip theo c gi tr hn km nhau l 0.8nm.

Ti mc Power cho php ta nhp cng sut pht quang c gi tr ph hp vi tng knh



10/18


Quy tc thay i gi tr ca cc tham s h thng

Thng s quan tm l :

Chiu di si G655 L1(Km), tn sc D1(Ps/nm.km), dc tn sc

S1(ps/nm2.km), v h s tn sc mode phn cc (PMD )


11/18


5. Kt qu thc hnh

5.1 Cc tham s m phng chi tit

Thng s ngun Laser

Thng s b ghp knh quang WDM:

Thng s si quang:



12/18


Thng s b khuch i EDFA:

5.2. Kt qu m phng

5.2.1. Kt qu m phng theo phng n thit k ban u

Quang ph tn hiu pht:



13/18


Quang ph tn hiu thu:

Cng sut tn hiu pht:



14/18


Cng sut tn hiu thu:

T l li bit BER:

Knh 1

Knh 2



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Knh 3



16/18


Knh 4



17/18


5.2.2. S thay i ca cc tham s t c BER = 10-12:

Kt lun:Bi bo co chng em xin c kt thc ti y.Mc d rt c gng trong

qu trnh thit k,tuy nhin vn cn mt s hn ch v thiu st,rt mong c s gp ca

thy gio v cc bn.



18/18


Em xin chn thnh cm n!

PTIT H10VT5 18 Nhm 11

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TTQ. Nhóm 4 - ban nho