Kit qua nghien ciru khoa hoc vd cdng nghe KHUECH DAI ...

Kit qua nghien ciru khoa hoc vd cdng nghe

KHUECH DAI RAMAN VA KHA NANG UNG DUNG TREN MANG VIEN THONG VIET NAM

KS. Pham Thj Hong Nhung

Tom tdt: Bdi viit gidi thieu vi cdng nghi khuech dai Raman va dua ra nhung danh gia ve kha ndng img dung cdc bd khuech dai Raman vao mang viin thdng Viet Nam.

1. Gioi thieu Co hai loai khuech dai quang duoc quan tam hien nay la khuech dai qua ig sgi pha erbium (EDFA) va khuech dai quang sgi Raman (FRA). Trong do, khuech dai EDFA la cong nghe da hoan thien va cac bo khuech dai EDFA da dugc kiem chiing hoat dong rat hieu qua trong cac he thong WDM don va da kenh. Trong thai gian gan day, khuech dai Raman dang dugc noi den nhu mot cdng nghe khuech dai bd trg cho khuech dai EDFA trong cac he thdng DWDM cu ly ldn va cue ldn do cac uu diem ve dac tinh nhieu thap, phd khuech dai rdng va ddng deu. Cac bd khuech dai Raman da bat dau dugc su dung tren mang vien thdng ciia mot sd nude tren the gidi.

0 nude ta, trong thai' gian tdi, mang vien thdng Viet Nam se khong ngung dugc nang cap va md rdng nham dap ung nhu cau luu lugng ciia tuang lai. Khi do, lua chgn cdng nghe khuech dai quang nhu the nao de vita dap ling dugc dung lugng truyen din, dam bao yeu ciu ky thuat ciia he thdng va vira kinh te se la mot cau hdi dat ra ddi vdi cac nha khai thac mang ludi.

Bai bao se torn tat nguyen ly, phan loai va gidi thieu dac diem ciia cac bd khuech dai Raman de lam co sd cho viec gia kha nang sii dung khuech dai Raman tren mang viln thdng ciia VNPT. 2. Nguyen ly ciia cac bo khuech dai Raman

Tan xa Raman la qua trinh phi tuyen ma nhd do anh sang tdi tren mot mdi trudng se duoc bien ddi sang mot tan sd thap han. Dua tren quan diem ca-lugng tii, hien tugng nay dugc md ta bang so dd tren Hinh 1.

Mot photon bom (Op se kich thich mot phan tu nhay len mot miic ao (trang thai khong cdng hudng). Phan tir nay nhanh chong bi roi xuong mot mire nang lugng thap hon ddng thai qua trinh nay lam phat xa ra mot photon tin hieu ov Cac dao ddng phan tir ciia vat lieu gdc da gay ra su chenh lech ve nang lugng giira photon bom va photon tin hieu. Cac miic dao ddng nay xac dinh dd dich chuyen tan sd va dang ciia dudng cong dd khuech dai Raman. Dd chenh lech tin sd (hay budc song) giua photon bam va photon tin hieu (0)p -ojs) dugc ggi la dich chuyen Stokes, va trong cac sgi truyen din thdng thudng cd loi pha Ge thi gia tri dich chuyen tan sd ldn nhat la khoang 13,2 THz.

Results of Science & Technology Reseach

Khi cac muc cong suat bom dii Ion, anh sang tan xa co the phat trien nhanh chong voi phan Ion nang luong bom duoc bien doi thanh anh sang tan xa. Qua trinh nay duoc goi la tan xa Raman kich thich (SRS), va day la co che khuech dai trong bo khuech dai Raman. SRS cd 3 dac diem rat quan trong la: SRS co the xay ra trong tat ca cac loai sgi quang; do photon bom bi kich thich len mire ao nen khuech dai Raman cd the xay ra tat bat ky budc song tin hieu nao neu lua chgn buoc song bom phu hgp; qua trinh khuech dai Raman xay ra rat nhanh chong (co vai fs)

Trang thai ao

Cac trang thai dao dong

Trang 'hai ca ban

Hinh 1: Qud trinh tan xa Raman tren quan diem ca-lucrng tu

Tir thuc te cho thay, SRS khong dd quan sat trong cac sgi quang sir dung cac chiim bom dang song lien tuc CW do nguong ciia chiing tuong ddi cao (~ 1 W). Tuy nhien, neu chiim Stokes co tan sd thich hop dugc phong ciing vdi chiim bom thi chiim Stokes se dugc khuech dai len dang ke nho chiim bom CW cd cac miic cdng suat - 100 mW. Bom va tin hieu cd the dugc phong cirng hudng (bom thuiin) hoac ngugc hudng (bom nghich) do ban chat gan dang hudng ciia SRS. Tuy vay, can hinh bom nghich thudng dugc quan tam hon trong thuc te vi ddi vdi cac he thdng cu ly ldn bi gidi han bdi cac tinh chat phi tuyen ciia sgi thi bom nghich cd the cho chat lugng truyen dan cao hon do cdng suat tin hieu se dan trai qua toan bd chieu dai tuyen. lam giam cac anh hudng phi tuyen. 3. Phan loai khuech dai Raman va dac diem

Phan loai khuech dai Raman

Cd hai loai khuech dai Raman la bd khuech dai Raman phan tan (DRA) va bd khuech dai Raman tap trung (LRA). Khuyen nghi ITU-T G.665 da dinh nghTa hai loai khuech dai Raman nay nhu sau:

Khuech dai Raman phan tan la cac bd khuech dai ma hieu ting khuech dai dat dugc qua hieu ung SRS tren sgi quang dugc sir dung lam mdi trudng truyen dan. Cac bd khuech dai nhu vay dugc ggi la phan tan vi mot phan hoac toan bd sgi truyen dan se dugc sir dung cho muc dich khuech dai.

Ket qua nghien ciru khoa hoc vd cdng nghe 173

- Khuech dai Raman tap trung la mot bo khuech dai ma hieu ung khuech dai dat duoc qua hieu irng SRS va tat ca cac thanh phan vat ly cua bo khuech dai duoc dat hoan toan ben trong thiet bi khuech dai.

Trong thuc te, cac bo khuech dai Raman phan tan thudng cd chieu dai > 40 km, cac bo khuech dai Raman tap trung thudng co chieu dai <15 km (khoang 5 km).

Hinh 2 la mot sd cau hinh ciia cac loai khuech dai Raman nay.

SJI iruyen dan (Soiechdai)

B6gh< J(hu£ch dai duong

truyen quang TinhiSu Sgi khuech dot

>ghdpWDM f f f \ i T j n h i-u

ily * ^ 7

a) Cau hinh bo khuech dai Raman b) Cau hinh bo khuech dai Raman phan tan (DRA) bom nghjch tap trung (LRA) bom hai hudng

Hinh 2: Cdu hinh cdc loai khuech dai Raman

Cac dac diem ciia khuech dai Raman

Khuech dai Raman cd mot sd uu diem ndi trdi so vdi EDFA. Cac uu diem nay cang trd nen ro ret hon vdi cac he thdng DWDM dung luong cao, cu ly ldn va ddi hoi nhung chi tieu nghiem ngat hon, nhat la cac mang toan quang.

- Dd phang cua phd khuech dai thap: Khuech dai Raman cd phd do khuech dai rat bang phang. Cac he thdng khuech dai Raman hien nay cd the dat dugc do phang ciia phd khuech dai <0,2dB khi su dung nhieu bam. Dieu do cho phep sd lugng bd khuech dai ghep chudi ldn gap it nhat 5 lan so vdi sd bd EDFA cd the mac chudi trong mot he thdng.

- He sd nhieu thap: Mot trong nhung uu diem quan trgng nhat ciia khuech dai Raman kha nang la cai thien OSNR tuyen truyen dan do dac tinh nhieu thap. Dac tinh nay dat dugc do dd khuech dai dugc phan bd dgc theo tuyen truyen dan.

- Bang tan bd khuech dai rdng: Bang tan bd khuech dai Raman rat rdng, cd FWHM khoang 60 nm. Cd the dat dugc phd khuech dai rdng hon nua (-100 nm) khi sii dung cac nguon bam da budc song.

Bang 1: So sanh cac dac tinh quan trong ciia khuech dai Raman va EDFA.

Results <</ Science \ Technology Reseach

Loai khuech dai

Bang tan khuech dai

Do khuech dai Do phang ciia KDQ

He so nhieu

EDFA 30 nm (tu 1530 -1560 nm) bang C

20 dB hoac cao hon tuy theo ndng do pha tap,

chieu dai sot va cau hinh bom

1 dB Ion khi he thong sir dung nhieu

LA

5 dB

FRA 100 nm (tu 1520 nm den 1620 nm) khi su dune 4 bom

10 dB. ty le vdi cong suat bom va chieu dai soi hieu

dung

0.2 dB < 0 dB (nhieu tuong

duong)

Tit cac dac diem cua khuech dai Raman a bang tren, cd the thay:

- Khuech dai Raman co the lam cai thien OSNR ciia tin hieu dan den tang cu ly khoang lap dien cua he thong

- Khuech dai Raman co the keo dai khoang each giiia cac tram lap quang, do do lam giam so bo khuech dai tren dudng truyen dan.

- Khuech dai Raman cho phep tang gap 3 lan so luong cac budc song cho phep so voi he thong chi sir dung EDFA.

- Tuy nhien. do do khuech dai ciia Raman thap khong dii bii suy hao ciia chang truyen dan nen FRA va EDFA thudng duoc sir clung ket hop vdi nhau trong cau hinh khuech dai lai EDFA/Raman de tan dung loi diem ciia ca 2 loai khuech dai nham dat duoc dac tinh he thdng cao nhat.

Chfnh vi cac ly do d tren ma khuech dai Raman duoc quan tam cho cac he thdng LH, ULH va cac he thdng DWDM dung luong cue ldn. 4. Kha nang sd dung khuech dai Raman tren mang vien thdng Viet Nam

Cac kha nang ling dung ciia bo khuech dai Raman

Nhu da de cap d cac phan tren, khuech dai Raman duoc don nhan nhu mot giai phap khuech dai bd sung ben canh khuech dai EDFA do kha nang cai thien OSNR, phd khuech dai bang phang va bang tan khuech dai rdng.

Do cac uu diem do ma khuech dai Raman duoc irng dung cho cac muc dich sau [2]:

Tang chieu dai chang truyen dan do cai thien OSNR: DRA cho phep tang chieu dai chang them 50%, tuong duong vdi giam 35% sd cac chang so vdi phuong an chi sir dung EDFA. Tuy nhien, vi OSNR ciing suy giam rat nhanh khi tang chieu dai chang truyen dan tham chf ngay ca khi sir dung DRA vdi do khuech dai tuong ddi cao, nen

Ket qua nghien cuu khoa hoc vd cdng nghe 175

ddi vai cac he thong LH va ULH, chieu dai chang truyen dan ldn nhat trong thuc te thudng nam trong dai (100 4-120) km

- Tang cu ly giua cac tram lap dien do tang OSNR: DRA da lam tang dang ke cu ly cua he thdng ULH, cho phep dat cu ly he thdng khoang 4000 km (-50 chang 80 km) do cai thien OSNR

- Tang dung lugng he thong: Vdi bang tan -100 nm, khuech dai Raman cho phep ghep so lugng kenh gap ba lan so lugng kenh cd the dugc ho trg bdi khuech dai EDFA (bang tan khoang 30 nm trong bang C). Dieu nay cue ky quan trgng vdi cac he thdng DWDM khi nhu cau ve dung lugng ngay mot tang cao.

Mat khac, khuech dai Raman cd the dugc sii dung cho cac he thdng DWDM vdi cac kenh budc song cd khoang each nhd. Vdi cac kenh cd khoang each nhd, su tuong tac phi tuyen giua cac kenh, dac biet la FWM va dieu che pha cheo, cd anh hudng rat nghiem trgng. Tuy nhien, khi su dung khuech dai Raman phan tan, cd the giam cac miic cdng suat phong ciia kenh nham giam cac tuong tac phi tuyen ma van duy tri dugc dac tinh OSNR cua he thdng.

Mac du khuech dai Raman cd nhieu uu diem nhu da ke tren, nhung do gia thanh ciia cac bd khuech dai Raman hien van d miic cao nen khuech dai Raman khong dugc su dung "mgi luc, mgi noi" ma chi dugc ling dung cho mot sd trudng hgp nhat dinh. Su can nhac cd su dung khuech dai Raman hay khong thudng dugc dua tren ca so chieu dai chang truyen din, hoac cu ly tuyen va nhu cau ve dung lugng he thdng. Cd the phan loai ling dung ciia khuech dai Raman cho cac trudng hgp sau:

Cdc he thdng khong tram hip co culy Ion (>160 km):

Bay la cac tuyen thudng gap d cac he thdng ket ndi hai vj tri a rat xa nhau, giua hai vi tri nay rat khd hoac khong the trien khai cac tram khuech dai trung gian do gap cac trd ngai vd vln de ky thuat nhu cap nguon, van de khai thac bao dudng khd khan... Cac tuydn cap quang bien vdi cau hinh feston, hoac cac tuyen khd khan cho viec dat tram lap la cac vi du didn hinh cho trudng hgp nay.

Cac dac diem thudng gap ciia cac tuyen nay la: khong sii dung khuech dai dudng truyen do khd khan trong cap nguon, bao dudng thiet bi; cu ly tuyen ldn; yeu clu dam bao dd tin cay cao; yeu cau dam bao kha nang md rdng, nang cap de dang.

- Neu tuyen cd cu ly ngan han 160 km thi khuech dai EDFA se la lua chgn dugc uu tien tai cac vi tri dau cudi.

- Ndu tuydn cd cu ly ldn hon 160 km thi khudch dai Raman se la giai phap bd sung ben canh EDFA.

Cac san pham khuech dai Raman ciia cac hang sii dung cho trudng hop ung dung nay deu cho phep dat cu ly tuyen - 400 km.

Results <'l Science & Technology Reseach

Cdc lie thong DWDM ULH co etc ly hang nghin km, dun<j I irons ldn

Mot ung dung rat quan trong ciia cua DRA la sir dung cho cac tuyen LH va ULH gom nhieu chang co cu ly hang nghin km. Vi du dien hinh cho trudng hop nay la cac tuyen dudng true tren dat lien, hoac tuyen cap quang bien.

Cac dac diem ciia cac tuyen nay la: cu ly hang nghin km; sd budc song > 40 (neu khoang each giira cac buoc song la 100 GHz), hoac > 80 (neu khoang each giua cac budc song la 50 GHz) vdi tdc dd bit 10 Gbit/s hoac 40 Gbit/s; cd sir dung cac thiet bj ROADM va OXC cho phep kenh cd the di qua khoang each ldn; yeu cau chi phi thap; yeu cau dam bao do tin cay cao; yeu cau dam bao kha nang md rdng. nang cap de dang

Viec sir dung khuech dai Raman cho cac tuyen nay se cho phep dat:

+ Dat cu ly khoang lap dien 4000 km vdi chieu dai chang 80 km

+ Dat chieu dai chang tdi uu (100 -H 120) km vdi cu ly khoang lap dien > 2000 km

+ Tdc dd bit: 10 Gbit/s, 40 Gbit/s

+ Sd budc song: Sd budc song > 40 (neu khoang each giira cac budc song la 100 GHz), hoac > 80 (neu khoang each giira cite budc song la 50 GHz)

Bang 2: Tdng hop so sanh ung dung EDFA va Raman trong he thong thdng (in quang

STT Tieu chi He thong sir dung EDFA He thong su dung Raman + EDFA

1 Nhieu, NF Cao 5 dB, thap nhat 3 dB Thap, < 0 dB

7 Phd he thdng -30 nm (bang C), tuong duong 40 budc song khoang each 100 GHz

- 100 nm

3 Tuyen cd tram lap quang OF A Chieu dai chang <100 km (80-rl20) km Cu ly khoang lap dien O/E dien hinh

< 600 km (vdi chieu dai chang <100 km),

dat 1500 km nhung phai giam chieu dai chang <70 km

> 2000 km

Ung dung dien hinh

+ Tuyen < 600 km tren dat lien + Tuyen cap quang bien vdi chieu dai chang (50-70) km

+ Tuydn cu ly - 1000, 2000 km tren dat lien va cap quang bien, cho phep sir dung bo xen re va chuyen mach toan cuiant:

Ket qua nghien ciru khoa hoc vd cdng nghe ill

4 Tuyen khong co tram lap OF A

< 160 km > 160 km

Ung dung dien hinh

+ Tuyen cu- ly ~ 160km, cd the dat xa hon ~300 km nhd bom tir xa nhung can phai cd soi EDF tren tuyen

+ Tuyln Feston cy ly > 160 km, co thi dat 400 km tren soi quang thuan

Kha nang ung dung khuech dai Raman tren mang vien thdng Viet Nam

Cac danh gia ve kha nang ling dung khuech dai Raman tren mang viln thdng Viet Nam d phan nay se dugc dua tren hien trang, djnh hudng phat trien mang truy! din quang ciia VNPT va kha nang ciia khuech dai Raman trong viec cai thien chat lugng he thdng.

- Xet ve hien trang mang truyen din quang ciia Viet Nam, thi dung lugng truyln din phd bien vln d miic STM-1 den STM-16, trong do tuyen DWDM dudng true Bac-Nam tren dat lien cd dung lugng 8xSTM-16. Phan ldn cac he thdng truyen din quang dlu cd cu ly thap, trong do he thdng DWDM dudng true 20 Gbit/s hien la he thdng :6 cu ly ldn nhat (Tuyen Ha ndi den Vinh: ~ 350 km, tuyln Vinh den Da nlng: ~ 450 km, Da Nang den Qui nhon: ~ 350 km, Qui Nhom den HCM : ~ 700 km, HCM den Can tho: -300 km).

Loai khuech dai quang dang sir dung tren mang ludi la EDFA vdi cu ly khoang lap dien dat dugc xap xi 600 km

Do vay, sir dung EDFA vln hoan toan phu hop va tdi uu ve chi phi. Tuy nhien, tren tuyen Qui Nhon-Hd Chi Minh vln phai dung them tram lap dien.

- Theo djnh hudng phat triln mang truydn din quang Viet Nam, thi sap tdi, he thdng cap quang bien Bac-Nam DWDM ciu hinh feston vdi dung lugng tdi da 80 Gbit/s se dugc xay dung, dung lugng mot budc song 2,5 Gbit/s, cu ly giua cac tram c$p bd ldn.

Tiep do, tang dung lugng he thdng true chfnh (he thdng cap quang dat hen va biin) theo yeu cau 2027.

He thdng truyen din true chfnh se dugc nang cip len dung lugng cao hon su dung cdng nghe WDM va se dugc kit ndi tdi he thdng true chinh mdi (tuyln cap bidn true Bac-Nam) tao thanh cau hinh mach vong SDH.

Do vay, phan dudi day se dua ra kha nang sir dung khuech dai Raman cho tuyen cap bidn feston va tuyen dudng true tren dat lien khi tiep tuc duoc md rdng.

Kha none dp duns khuech dai RAMAN tren tuven cap auang biin B&c-Nam cdu hinh Feston

Day la tuyen cap bien cd y nghTa vd ciing quan trgng ddi vdi viec an ninh thdng tin va tao co id ha tang viln thdng hien dai cho cdng cudc phat triln cua dat nude.

Results of Science & Technology Reseach

Dac diem cua tuyen cap bien Bac-Nam cau hinh Feston la co dung luong 20 Gbit/s (8x2.5 Gbit/s). cu ly giua cac tram cap bd tu 152 den 304 km, ddi boi dp tin cay cao va dam bao kha nang md rdng nang cap de dang trong tuong lai.

Bang 3: Cu ly giua cac tram cap bd tren tuyen cap bien Bac -Nam Stt Tram - Tram Don vi Dp dai 1 Ha Npi - Hai Phong - Thanh Hoa km 170

Thanh Hoa - Vinh km 152 3 Vinh - Dong Ha km 228 4 Dong Ha - Da NSng km 304 5 Da Niing - Quang Ngai km 235 6 Quang Ngai - Quy Nho'n km 208 7 Quy Nho'n - Nha Trang km 216 8 Nha Trang - Phan Thiei km 273 9 Phan Thiet - Vung Tau kin 178 10 Vung Tau - Sdc Trang km 258

Vdi dac diem cua tuyen nhu tren, chiing tdi da lua chon phuong thuc sir dung khuech dai quang cho tuyen nay nhu sau [2]:

Vdi cu ly giira cite tram cap bd nhu tren, ngoai tuyen Thanh Hoa-Vinh cd cu ly 152 km, thi cac tuyen con lai deu cd cu ly ldn > 160 km.

Vdi cac cu ly tuyen > 160 km va xem xet nhu cau md rdng dung luong trong tuong lai thi cd the thay rang sir dung khuech dai Raman cho cac tuyen nay la rat phii hop.

> Neu chi sir dung EDFA cho cac tuyen nay se khong kha thi hoac phai thiet ke tuyen cap spi quang hon bop cd soi EDF de cd KDQ bom tir xa , chi phi dau tu ldn cho ca 8 cap spi trong khi do ban dau nhu cau chi sir dung 1 cap spi. ngoai ra khd khan cho viec nang cap tuyen sau nay.

> Lira chon md hinh khuech dai Raman phan tan ket hop EDFA do cac uu diem da de cap d tren va do thiet ke tuyen don gian vi chi sir dung spi truyen din thdng thudng (G.652, G.655,..)

> Co the nang cap dung Iirpng khi cd nhu cau theo cac phuong an tang sd kenh (den 16-32 kenh) hoac tang toe dp cua kenh (10 den 40 Gbit/s).

> Ket hop vdi cdng nghe FEC, cac san pham khuech dai Raman thuong mai cua cac hang deu cd kha nang dat cu ly - 400 km .

Ket qua nghien ciru khoa hoc va cdng nghe 179

Khu nans tins duns khuech dai Raman tren tuyen duong true DWDM tren dat lien

Viec thiet ke tuyen dudng true Bac-Nam DWDM tren dat hen se phai xet den mot so yeu to nhu: tan dung nha tram san co, tang khoang lap quang de giam chi phi tram lap; tang cu ly khoang lap dien 3R (REG) de giam chi phi bo bien ddi OE va de dang nang cap tdc do; luu lugng xen re trung gian it, chii yeu ket cudi tai cac diem ldn nhu Ha ndi, Da nang, HCM cd nhu cau sir dung cac bd OADM va OXC quang; tdc dd kenh/ 1 budc song tang tir tir theo nhu cau sir dung theo cac budc 2,5 Gbit/s, 10 Gbit/s, 40 Gbit/s va khong can ldn ngay.

Ngoai he thdng WDM 20 Gbit/s hien nay, trong tuong lai mang dudng true tren dat lien ciia VNPT se nang cap, trien khai them cac he thdng mdi. Sau day dua ra cac md hinh, kich ban ap dung khuech dai Raman trong he thdng WDM tren dat hen.

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7/zn/r 5: C<7/( /ii«/i /uyew cap quang dudng true 20 Gbit/s

Trong cau hinh tuyen cap quang tren, gia sir cac tram xen re khong thay ddi vi tri. Cac RING nang cap se bao gdm: Ha ndi den Vinh: - 350 km, Vinh den Da nlng: ~ 450 km, Da Nang den Qui nhan: ~ 350 km, Qui Nhan den HCM : ~ 700 km, HCM den Can tha: -300 km

Vdi he thdng nay, tuy theo dd dai tuyen ma se lira chgn hinh thiic sir dung rieng EDFA hay sir dung ket hgp EDFA va khuech dai Raman:

- Hau het cac tuyen WDM tren cd cu ly dudi 500 km do vay viec su dung he thdng WDM theo G.692 la phii hgp, hieu qua ve chi phi.

- Xet .ardng hgp tuydn tir Qui nhon den HCM cd cu ly 114+125+106+58+94+117+ 85= 699 km bao gdm ca tram xem re quang OADM.

r Neu sir dung cong nghe EDFA theo G.692 thi can 1 tram lap dien 3R dat tai Phan Rang va Budn me thudt nhu he thdng 20G hien nay.

> Ngu trong tuong lai nhu cau du ldn, dung lugng hd thdng tiep tuc dugc md rdng theo phuong an tang tdc dd bit ciia kenh len 10 Gbit/s thi ap dung bd

180 Results of Science & Technology Reseach

khuech dai Raman se cho phep tang cu ly truyen dan trong suot, cho phep bo bo lap dien tai cac diem trung gian Phan Rang va Buon Me Thupt.

Khd nine dp duns Raman tren mans auans duong true muc tieu cua VNPT sau 2010 Theo ket qua ciia de tai "Giai phap cdng nghe phat trien mang vien thdng NGN ciia Viet Nam 2006-2010", Ma sd: 031-2005-TCT-RDS-VT-09 [3], thi mang quang dudng true ciia VNPT sau 2010 cd muc tieu chinh nhu sau:

• Xay dung mot mang chuyen mach quang cho mang true vdi tdc dp kenh tren 10 Gbit/s va 3 mang vung trung tam: Ha ndi, Da nang va TP. Hd Chi Minh.

• Ddi vdi mang true: thidt lap cac chuyen mach quang vdi muc tieu theo topo mesh nham phuc vu cho truyen tai luu luong IP/MPLS trong mang true (Hinh 4), ddng thai su dung phuong an dam bao viec bao ve phuc hoi dua tren cac tuyen cap quang quoc Id 1 A, tuyen cap quang dudng Hd Chi Minh, tuyen cap quang quang bien .

Mang vung 2

Hinh 4: Mang chuyen mach quang mang true muc tieu cua VNPT

Vdi giai phap su dung cac bp OXC chuyen ludng quang cd tai tao lap dien 3R, cac tuyen DWDM tren dat hen can xay dung gdm cd: Ha noi -Vinh tren tuyen cap quang HCM cu ly ~ 350 km, Vinh- Da nang tren tuyen cap quang QL1A G.652 - 500 km, Vinh - Buon me thudt tren tuyen cap quang HCM dai -1200 km, Qui nhan den - Buon me Thupt tren tuyen QL 1A dai ~ 200 km, Buon me Thupt - TP HCM tren tuyen cap quang HCM dai - 300 km

Tuong tu nhu trudng hap tren, khuech dai EDFA va khuech dai Raman se dugc lua chon sii dung rieng re hoac ket hop tuy theo dp dai ciia tuyen:

Ket qua nghien cuu khoa hoc vd cdng nghe 181

Tai lieu tham khao [1]. Clifford Headley, "Raman amplification in fiber optical communication system",

Elsevier Academic Press, ISDN: 0-12-044506-9

[2]. De tdi cap Bp, "Nghien ciru ky thuat vd cdng nghe khuech dai Raman vd khd ndng img dung trong mang vien thdng Viet Nam ", Md sd: 96-06- KHKT- RD

[3J. De tdi "Gidi phap cdng nghe phat trien mang vien thdng NGN ciia Viet Nam 2006-2010", Ma so: 031-2005-TCT-RDS-VT-09

182 Results of Science & Technology Reseach

GIAI PHAP DINH TL YEN BAO VE VONG RPR AO TREN MANG QUANG THE HE SAU

ThS. Vu Hoang Son

Tom tdt: Gidi phap thiet bi mang quang tich hop da dich vu (MSxP) hien duoc nhieu nhd khai thac truven thdng lira chon vd then khai tren the gidi vd d I let nam. I di dac diem tich hop da cdng nghe nhu RPR. Ethernet. PBT. MPLS, NG-SDH vd WDM tren mot nen thiit bi cho phep cung cap gidi phap da dich vu vd mem deo. dap img nhu can da dang trong trien khai thuc ti. Dien hinh, khd ndng cung cap cdc vong RPR do tren nen ldp mang quang nhu SDH hay WDM cho phep cung img cdc dich vu mdi hudng dir lieu cho khach hang nhu Ethernet, I 'PS. SAX.... Tuv nhien. ciing cd nhieu thach thirc nay sinh trong qua trinh trien khai vd dp dung tren mang ludi. Tren co so ket quit do kiem vd phan tich cdc img dung thuc te[l], bdi viel nay de xudl chien luge hoi phuc vd giai phap dinh tuyen bao ve vong RPR ao sao cho rein dam hao ldi im ve luu luong ddng thai van duy tri mire bao ve mang khi cd tinh den cdc chirc ndng khdi phuc d cdc ldp mang khac nhau, ddng thoi ciing dua ra cdc khuyen nghi ve lira chon cdng nghe. 1. Gioi thieu Voi toe do phat trien theo ham so mii ciia cac dich vu da phuong tien tren co sd IP. da thiic day viec ap dung cong nghe mang truy nhap bang rong (xDSL. WiMax. FTTx...) va se gay ra su tac nghen trong vung mang do thi (MAN). Trong khi do. vdi sire ep ciia canh tranh. cac nha khai thac mang khong muon dau tu qua nhieu vao ha tang mang. Vi vay cac giai phap. cong nghe mdi can tim dung co sd ha tang hien co va can phat trien, ung dung tren cac cong nghe hien co nhu SDH va WDM. Giai phap thiet bi mang quang tich hop da dich vu MSxP (MSPP. MSTP, MSSP) hien duoc xem la giai phap phii hop nhat duoc nhieu nha khai thac truyen thong lira chon va trien khai tren the gidi va d Viet nam dien hinh la VNPT[1]. Vdi dac diem tich hop da cong nghe nhu RPR, Ethernet, PBT, MPLS, NG-SDH va WDM tren mot nen thiet bi cho phep cung cap giai phap da djch vu va mem deo, dap irng nhu cau da dang trong trien khai thuc te. Tuy nhien, trong moi trudng thich hop da cong nghe ciing nay sinh nhieu thach thiic can giai quyet nhu: cac van de ve chuyen doi giao thuc, tranh chiic nang chong cheo. duy tri chat luong djch vu....giira cac ldp mang va cong nghe. Trong qua trinh trien khai va ap dung, viec tan dung triet de cac mat manh va giam thieu cac mat yeu ciia cac cong nghe, dien hinh la viec lira chon va ap dung cong nghe phii hop cho tirng irng dung cu the la mot trong nhirng thach thuc ldn doi vdi nha khai thac mang. Trong qua trinh do kiem cho thay cac thiet bj NG-SDH ciia mot so Hang nhu Huawei, Fujitsu. ZTE... [1] deu co kha nang cung cap cac djch vu Ethernet bang mot hoac to hop mot so cac cong nghe nhu RPR, MPLS, SDH nhung cirng co cac kha nang va miic do mem deo khac nhau. Dien hinh, cong nghe RPR ket hop vdi cac giao thirc GFP, VCAT, LCAS cho phep cung cap cac vong RPR ao tren nen ldp mang quang nhu SDH hay WDM nhd do cung irng cac djch vu mdi hudng dir lieu cho khach hang (VPN. SAN...). Tuy nhien, cung co nhieu thach thirc nay sinh trong qua trinh trien khai va ap dung RPR tren mang ludi. Tren co so do kiem va phan tich, danh gia thiet bi quang NGSD11[l], bai bao nay de cap tdi mot so irng dung dien hinh ciia cong nghe RPR. va dua ra giai phap va khuyen nghj cho mot