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Bai 2: o a Bc Song Tai Lieu Thc Hanh

Thc Hanh Thong Tin Quang 33

O A BC SNG

1. GII THIU MY O A BC SNG FTB-5320

1.1.NG DNG:

- o dch chuyn bc sng o nh hng ca mi trng ln card pht v card thu.- nh gi tri ph di hn ca cc linh kin tch cc.- o c tnh v cht lng ca cc con chip v module laser WDM DFB.- o gim st mng DWDM.- Cn chnh my o phn tch ph quang.- o c tnh v kim tra linh kin thng.- o phn phi li ph ca EDFA.- Cn chnh laseriu chnh c bc sng (tunable lasers)1.2.NGUYN L O A BC SNG

- My o a bc sng to ra kt qu v hin th cng sut theo bc sng.- Kt qu c c nhs dng cng ngh giao thoa.2. AN TON KHI SDNG MY O A BC SNG

- Khng c gn hoc tho si quang khi ngun quang ang pht.- Khng c nhn trc tip vo u si quang.- S dng my o quang s lm tng nhn p (increase eye hazard)- Khng c gn hoc tho module khi khung my chnh (FTB-400 Universal) ang trng thi ON.

- Khi LED ch thlaser onang chp, iu c ngha c module no ang pht x tnhiu quang. Hy kim tra ngay tt c cc module.

3. KHI NG TOOLBOXStart All Progarms EXFO Toolbox

4. CHN CHC NNG Multi-Wavelength Meter

Hnh 1. Khi ng Toolbox

Sau khi khi ng xong, ta c ca s chnh nh hnh 2


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Hnh 2. Khi ng chng trnh Multi-Wavelength Meter.

5. CI T CC THNG S CHO MY O A BC SNG

5.1. Ci t n vo cng sut.

n vo cng sut c th l Watt hoc dBm. Khuyn co s dng n v dBm.

T ca s chnh nh hnh 2, ta thc hin cc bc sau chn n vo cng sut:

(1) Nhn Setup

(2) Chn General

(3) Chn n vo l dBm hay Watt.

(4) Nhn Exit Setup

Xem hnh 3.


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Hnh 3. Ci tn vo cng sut

5.2. Ci t n vo bc sng.

n vo bc sng l nm hoc Thz.

T ca s chnh nh hnh 2, ta thc hin cc bc sau chn n vo bc sng:

(1) Nhn Setup

(2) Chn General

(3) Chn n vo l nm hay THz.

(4) Nhn Exit Setup

Xem hnh 4.


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Hnh 4. Ci tn vo bc sng

5.3. Ci t ch hin th d liu lin knh (hai knh k cn)

D liu lin knh lin quan n vng ph gia hai bc sng nh k cn, bao gm

khong cch hai bc sng nh v chnh lch cng sut hai nh.

T ca s chnh nh hnh 2, ta thc hin cc bc sau hin th d liu lin knh:

(1) Nhn Setup

(2) Chn General

(3) Chn Show Interchannel Data

(4) Nhn Exit Setup

Xem hnh 5.

Hnh 5. Ci t hin th dliu lin knh

5.4. Ci t ngng pht hin knh (Detection Threshold)

Ngng pht hin knh l khong chnh lch gia mc nhiu v mc nh nh nht ca

knh c th c pht hin.

T ca s chnh nh hnh 2, ta thc hin cc bc sau hin th d liu lin knh:

(1) Nhn Setup

(2) Chn General

(3) Nhp gi tr ngng ca sSignal Above Noise ca Detection Threshold.

Nu cng sut biu din theo dBm th ngng ny biu din theo dB. Gitr c th chp nhn l t 0dB n 10dB.


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Nu cng sut biu din theo Watts th ngng ny biu din theo %. Gitr c th chp nhn l t 0% n 900%.

V d: tng ngng pht hin knh vi h s 2 th ta ci thng s ny l 3dB

hoc 100%.

(4) Nhn Exit Setup

Lu : Nu my o a bc sng ch Offline th khung ny ch disable(Hide)

Xem hnh 6.

Hnh 6. Ci t ngng pht hin knh.

5.5. Chn cng sut c tham chiu.

Gi trc tham chiu ca mt knh cho php chng ta so snh mi nh pht hin c

vi 1 trong 3 cng sut c th tham chiu.

Cng sut c tham chiu l chnh lch gia cng sut P ca mt knh no vi

cng sut tham chiu Pavg. V d: P-Pavg l cng sut c tham chiu ca cng sut nh P s

dng cng sut tham chiu Pavg. N c hin thct cui cng ca bng kt qu (Results).

ci t cng sut c tham chiu, t ca s chnh nh hnh 2 ta thc hin cc bc

sau:

(1) Nhn Setup

(2) Chn General(3) Chn cng sut c tham chiu Referenced Power:

P-Pavg: cng sut trung bnh, l tng ca cc cng sut nh chia cho tngsnh.

P-Pn: Cng sut ca mt nh no (c chnh c th n). P-Ppeak: cng sut nh, l cng sut ca nh mnh nht.

(4) Nhn Exit Setup


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Hnh 7. Chn cng sutc tham chiu.

5.6. Chn mi trng truyn

Mi trng truyn (khng kh hoc chn khng) l mi trng m bc sng sc tnh

ton.

Chng ta chn mi trng l khng kh (Air) nu chng ta mun bc sng trong chn

khng c chuyn thnh bc sng trong khng kh nhit no .

chn mi trng truyn, t ca s chnh nh hnh 2 ta thc hin cc bc sau:

(1) Nhn Setup

(2) Chn General

(3) Chn mi trng truyn t khung Medium:

Nu chn Air th chng ta phi nhp gi tr nhit vo k bn (gi tr t0on 50oC)

(4) Nhn Exit Setup

Hnh 8. Chn mi trng truyn.


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- Nu nh ca 1 knh no nm ngoi knh nh ngha th n sc gim st v

hin th kt quo trong danh sch. Nu khng th khng hin th.

- Nu c t hai knh tr ln c nh nm ngoi knh nh ngha th ch c knh c nh

mnh nht c theo di.

nh ngha cc knh tham chiu ny, chng ta cn phi xc nh cc thng s trong

danh sch knh (cc ct tng ng) trong bng Channel (Channel tab).

Thng S M t

Ch S th t knh trong danh sch.

ID Tn ca knh. Phi nh hn hoc bng 8 k t.

Center Bc sng (nm) hoc tn s (THz) trung tm ca knh (v tr ca nh).

Width rng ca mt knh, c n v l GHz. Gi tr cho php: t 5GHz n 2000GHz.

Alarm Khong dao ng cho php ca Center, c n v l GHz. Nu nh ca knh nmngoi khong ny th my s pht tip bp v nh du !.

P Max Gii hn trn ca cng sut nh. Nu cng sut nh ca mt knh ln hn gi tr

ny th my s pht ra ting bp v nh du !. Gi tr cth t -39,9dBm n

+10dBm. Gi trP Max phi lun ln hn P Min.

P Min Gii hn di ca cng sut nh. Nu cng sut nh ca mt knh nh hn P Min

my s pht ra ting bp v nh du !. Gi trP Min t -40,0dBm n +9,99dBm.

Gi trP Min phi lun nh hn P Max.

a) nh ngha cc knh mi c khong cch bng nhau:nh ngha cc knh c c tnh ging nhau, ta thc hin cc bc sau:

(1)Nhn Setup.(2)Chn Channel.


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(3)Chn Equal Spacing.Lu : tt c cc knh ang c trong danh sch sb xa ht.

(4)T hp thoi Equal Spacing ta nhp cc thng s vo: Channel Count: s knh hin din trong si quang ta cn o. Gi tr t 1

n 100


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Channel Spacing: khong cch gia cc knh. Gi tr t 20GHz n1000GHz.

First Ch. Center: V tr ca knh u tin (Gi tr bc sng trung tm caknh u tin).

Channel Width: rng ca tt c cc knh trn si quang cn o. Gi trin hnh l 10% khong cch knh (Channel Spacing). V d: nu khong

cch knh l 100GHz th rng knh khong 10GHz. Channel Alarm Width: rng cho php di chuyn ca bc sng trung

tm (nm trong rng knh). Thng gi tr ny l 90% rng knh

(Channel Width). V d: nu chng ta c rng knh l 10GHz th

rng cnh bo l 9GHz.

Channel Alarm Max: Gii hn trn ca cng sut nh. Channel Alarm Min: Gii hn di ca cng sut nh.

(5)Nhn OK. Danh sch knh s xut hin.(6)Nhn Exit Setup trv mn hnh chnh.

6. TIN HNH O A BC SNG

6.1. Mmt file lu tr.

m(open) mt file, t ca s chnh hnh 2, chng ta thc hin nh sau:

(1)Chn Storage(2)Xc nh ng dn (File Setup) v file cn m(Recall File)


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(3)Xong bc (2) ta chn Exit Storage.

6.2. Chn loi th hin th.

Trace cho a bc sng thng hin th cng sut theo bc sng, nhng c th hin th

dng tm lt (bar graph) hoc chi tit nh (peak graph)


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6.3. c kt quo ch WDM:

thy c kt qu ca cc knh, ta thc hin nh sau:

(4)Chn bng Result.(5)

cun danh sch cc knh, chng ta s dng cc phm mi tn UP v DOWN


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Thng tin trn bng Result ca mi knh c phn tch nh sau:

(1)Ch (Channel ID): s th t knh(2)W (nm) (Channel Wavelength): Bc sng knh.(3)P (Channel Peak Power): Cng sut nh ca knh (n v ph thuc vo n v mnh

chn)(4): signal-to-noise ratio to the left () of the

channel peak

(5)P-Pavg (orP-Pn orP-Ppeak): referenced power (in the same unit as the current powerunit).

(6)Wavg (nm), Pavg: bc sng trung bnh v cng sut trung bnh ca cc knh WDMnhn c.

(7)Ptot: cng sut tng cng ca cc knh WDM trong si quang kim tra.6.4. S dng Markero.

Chng ta c th s dng Markero thng tin cc knh.

di chuyn Marker,chng ta thc hin:

(1)Chn bng Measurements.(2)Chn Marker mun di chuyn (A hoc B), s dng phm mi tn di chuyn hoc dng

chut.

UP

DOW


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Marker A

Chn loi MarkerPhng to/ Thu nh ti v tr ca

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