Nidaamka EPON, OLT wuxuu ku xiran yahay ONUs badan (unugyada shabakada indhaha) iyada oo loo marayo POS (pasive optical splitter).Sida xudunta u ah EPON, OLT modules-yada indhaha ayaa si toos ah u saameyn doona shaqada nidaamka 10G EPON oo dhan.
1.Hordhaca 10G EPON moduleka indhaha ee OLT
10G EPON simmetrical OLT moduleka indhaha ayaa isticmaala soo dhawaynta kor u kaca iyo hoos u dhigida hababka gudbinta joogtada ah, kuwaas oo inta badan loo isticmaalo beddelka indhaha / korantada ee nidaamyada 10G EPON.
Qaybta helaysa waxay ka kooban tahay TIA (amplifier transimpedance), APD (Avalanche Photodiode) oo ah 1270/1310nm, iyo laba LA (amplifiers xaddidan) oo ah 1.25 iyo 10.3125 Gbit/s.
Dhammaadka gudbinta waxa uu ka kooban yahay 10G EML (laser modulation modulation elektro-nuugista) iyo 1.25 Gbit/s DFB (laser jawaab celin qaybsan), iyo hirarka qiiqiisu waa 1577 iyo 1490nm, siday u kala horreeyaan.
Wareegga wadista waxa ka mid ah wareegga dijitaalka ah ee APC (Automatic Power Control Power Control) iyo TEC (magta Heerkulka) wareegga hirarka 10G laser deggan.Korjoogteynta gudbinta iyo helista cabbirka waxaa fuliyaa hal-kumbuyuutar-yar oo chip-ka ah sida uu qabo nidaamka SFF-8077iv4.5.
Sababtoo ah dhamaadka helitaanka moduleka indhaha ee OLT wuxuu isticmaalaa soo dhawaynta dilaaca, wakhtiga dejinta soo dhawaynta ayaa si gaar ah muhiim u ah.Haddii wakhtiga dejintu uu dheer yahay, waxay si weyn u saamayn doontaa dareenka, waxayna xitaa sababi kartaa soo dhawaynta dilaaca inay si sax ah u shaqayn weydo.Marka loo eego shuruudaha IEEE 802.3av borotokoolka, wakhtiga la aasaasayo ee 1.25Gbit/s soo dhawaynta dilaaca waa in ay ahaataa <400 ns, iyo dareenka soo dhawaynta dilaaca waa in uu noqdaa <-29.78 dBm oo leh waxoogaa khalad ah 10-12;iyo 10.3125 Gbit/s Wakhtiga dejinta soo dhawaynta dilaaca waa in uu ahaadaa <800ns, iyo dareenka soo dhawaynta dilaaca waa in uu noqdaa <-28.0 dBm oo leh waxoogaa khalad ah oo ah 10-3.
2.10G EPON simmetrical OLT naqshadaynta moduleka indhaha
2.1 Naqshadaynta nidaamka
10G EPON simmetrical OLT Optical Module wuxuu ka kooban yahay triplexer (module saddex geesood ah oo fiber ah), gudbinta, qaadashada, iyo la socodka.Triplexer-ku wuxuu ka kooban yahay laba laysarka iyo qalabka wax baadha.Iftiinka la kala qaado iyo iftiinka la helay ayaa lagu dhex daraa aaladda indhaha iyada oo loo marayo WDM (Wavelength Division Multiplexer) si loo gaaro gudbinta laba jiho ee fiber-ka ah.Qaab dhismeedkeeda waxa lagu muujiyay sawirka 1.
Qaybta gudbintu waxay ka kooban tahay laba lasers, kuwaas oo shaqadooda ugu weyni ay tahay in loo beddelo 1G iyo 10G calaamadaha korantada ee calaamadaha indhaha, siday u kala horreeyaan, iyo in la ilaaliyo xasilloonida awoodda indhaha ee xaalad xiran oo xiran iyada oo loo marayo wareegga dijitalka ah ee APC.Isla mar ahaantaana, kombuyutarka hal-chip-ka ah ayaa koontaroolaya xajmiga isbeddelka hadda jira si loo helo saamiga baabi'inta ee looga baahan yahay nidaamka.Wareegga TEC waxaa lagu daraa wareegga gudbinta ee 10G, kaas oo si weyn u dejinaya hirarka dhererka dhererka laser 10G.Qaybta helaysa waxay isticmaashaa APD si ay ugu beddelato calaamadda indhaha ee dillaacday ee la ogaaday una beddelo signal koronto, oo ay soo saartaa ka dib kordhinta iyo qaabaynta.Si loo hubiyo in dareenka uu gaari karo heerka ugu habboon, waxaa lagama maarmaan ah in la siiyo cadaadis sare oo deggan APD heerkul kala duwan.Kumbiyuutarka hal-chip ah wuxuu ku gaaraa yoolkan isagoo xakameynaya wareegga-korontada sare ee APD.
2.2 Dhaqangelinta soo dhawaynta dilaaca laba-heer
Qaybta helaysa ee 10G EPON summetric OLT optical module waxay isticmaashaa habka helista dilaac.Waxay u baahan tahay inay hesho calaamadaha dillaaca ee laba heer oo kala duwan oo ah 1.25 iyo 10.3125 Gbit / s, taas oo u baahan qaybta helitaanka si ay u awooddo inay si fiican u kala soocdo calaamadaha indhaha ee labadan heerar kala duwan si loo helo calaamado koronto oo deggan.Laba qaab oo loogu talagalay hirgelinta soo dhaweynta laba-qiimaheeda dilaaca ee modules-yada OLT ayaa halkan lagu soo jeediyay.
Sababtoo ah soo gelinta ishaarada indhaha waxay isticmaashaa tignoolajiyada TDMA (Time Division Multiple Access), kaliya hal heer oo iftiin dilaac ah ayaa laga yaabaa inuu jiro isku mar.Calaamadaha wax soo gelinta waxa lagu kala saari karaa qaybta indhaha iyada oo loo marayo 1: 2 kala qaybisa indhaha, sida lagu muujiyey Jaantuska 2. Ama isticmaal kaliya qalabka wax baadha si aad ugu beddesho calaamadaha 1G iyo 10G ee calaamadaha korantada ee daciifka ah, ka dibna kala saar laba koronto. calaamado leh heerar kala duwan iyada oo loo marayo baaxad weyn oo TIA ah, sida ku cad sawirka 3.
Nidaamka ugu horreeya ee lagu muujiyey Jaantuska 2 wuxuu keenayaa khasaare gelinta ah marka iftiinku dhex maro 1: 2 kala qaybiyaha indhaha, kaas oo ay tahay inay xoojiso calaamadda indhaha, sidaas darteed cod-weyneeye indhaha ayaa lagu rakibaa horteeda kala qaybiyaha indhaha.Calaamadaha indhaha ee kala go'ay ayaa markaa lagu sammeeyaa beddelaad indho-indheyn / koronto ah oo ay sameeyaan baarayaal heerar kala duwan leh, ugu dambeyntiina laba nooc oo soosaar koronto ah ayaa la helay.Khasaaraha ugu weyn ee xalkan ayaa ah in cod-weyneeye indhaha ah iyo 1: 2 kala qaybisa indhaha la isticmaalo, waxaana loo baahan yahay laba qalab si loo beddelo calaamadda indhaha, taas oo kordhisa kakanaanta hirgelinta iyo kordhinta kharashka.
Nidaamka labaad ee lagu muujiyey Fig.3, signalka indhaha wax soo galinta wuxuu u baahan yahay oo kaliya inuu dhex maro qalabka wax bare iyo TIA si loo gaadho kala soocida qaybta korantada.Xuddunta xalkani waxa ay ku jirtaa xulashada TIA, taas oo u baahan TIA si ay u yeelato xadhkaha xawaaladaha ee 1 ~ 10Gbit / s, isla mar ahaantaana TIA waxay leedahay jawaab degdeg ah gudaha bandwidth this.Kaliya iyada oo loo marayo qiyaasta hadda ee TIA ayaa si dhakhso ah u heli karta qiimaha jawaabta, dareenka helitaanka ayaa si wanaagsan loo dammaanad qaadi karaa.Xalkani wuxuu si weyn u yareynayaa kakanaanta fulinta wuxuuna ilaaliyaa kharashaadka.Naqshadaynta dhabta ah, waxaan guud ahaan ku dooranaa nidaamka labaad si aan u gaarno soo dhaweynta laba-qiimaheeda dilaaca.
2.3 Naqshadeynta wareegga qalabka ee dhamaadka helitaanka
Jaantuska 4 waa wareegga qalabka ee qaybta soo dhawaynta.Marka ay jirto gelinta indhaha ee dilaaca, APD waxay u beddeshaa signalka indhaha oo u beddelaa calaamad koronto oo daciif ah waxayna u dirtaa TIA.Digniinta waxa ku xoojisay TIA oo 10G ama 1G signal koronto ah ku kordhisay.Calaamadda korantada ee 10G waxa ay gelisaa 10G LA iyada oo loo marayo isku xidhka togan ee TIA, iyo 1G signalka korantada waxa uu gelayaa 1G LA iyada oo la marayo isku xidhka taban ee TIA.Capacitors C2 iyo C3 waa isku-xireyaasha capacitors loo isticmaalo in lagu gaaro 10G iyo 1G AC-ku-xidhan wax soo saarka.Habka AC-ku-xidhan yahay ayaa la doortay sababtoo ah wuu ka fudud yahay habka DC-ku-xidhan.
Si kastaba ha ahaatee, isku xirka AC wuxuu leeyahay dallacaadda iyo soo-saarka capacitor-ka, iyo xawaaraha jawaab-celinta calaamaduhu waxay saameeyaan kharashka iyo soo-dejinta wakhtiga joogtada ah, taas oo ah, signalka lagama jawaabi karo wakhtiga.Habkani waa hubaal inuu lumin doono qadar go'an oo ah wakhtiga dejinta, markaa waa muhiim in la doorto inta uu le'eg yahay awooda isku xidhka AC.Haddii la doorto capacitor yar oo isku xidha, wakhtiga dejinta waa la soo gaabin karaa, iyo signalka ay gudbiso ONU wakhti kasta oo boos ah si buuxda ayaa loo heli karaa iyada oo aan saamaynaynin saamaynta soo dhawaynta sababtoo ah wakhtiga dejinta soo dhawayntu aad buu u dheer yahay iyo imaatinka wakhtiga xiga Afyare.
Si kastaba ha ahaatee, awoodda aadka u yar waxay saameyn doontaa saamaynta isku-xidhka waxayna si weyn u yaraynaysaa xasilloonida soo dhaweynta.Awoodda weyn waxay yarayn kartaa jitterka nidaamka waxayna wanaajin kartaa dareenka dhamaadka helitaanka.Sidaa darteed, si loo tixgeliyo waqtiga dejinta soo dhaweynta iyo dareenka soo dhaweynta, capacitors C2 iyo C3 ee ku habboon ayaa loo baahan yahay in la doorto.Intaa waxaa dheer, si loo hubiyo xasilloonida calaamadda korantada ee gelinta, korantada isku-xirnaanta iyo iska caabbinta u dhigma ee 50Ω waxay ku xiran tahay terminalka taban ee LA.
LVPECL (Low Voltage Positive Emitter Coupling Logic) wareeg ah oo ka kooban iska caabiyeyaasha R4 iyo R5 (R6 iyo R7) iyo 2.0 V DC il danab iyada oo loo marayo soo saarista calaamadaha kala duwan ee 10G (1G) LA.signal koronto.
2.4 Qaybta bilawga
Qaybta gudbinta ee 10G EPON symmetric OLT moduleka indhaha ayaa inta badan loo qaybiyaa laba qaybood oo kala ah 1.25 iyo 10G gudbinta, kuwaas oo siday u kala horreeyaan u soo dirayaa calaamado leh hirar dhererkiisu yahay 1490 iyo 1577 nm xagga hoose.Qaadashada qaybta gudbinta ee 10G tusaale ahaan, lammaane 10G ah oo calaamado kala duwan ah ayaa gelaya chip CDR (Saacada Qaabaynta), AC-ku-xidhan yahay chip darawalka 10G, ugu dambayntiina si kala duwan ayaa loo geliyaa laser 10G ah.Sababtoo ah isbeddelka heerkulka ayaa saameyn weyn ku yeelan doona dhererka hirarka qiiqa laysarka, si loo dejiyo mawjadda dhererka illaa heerka loo baahan yahay borotokoolka (hab-ku-socodka wuxuu u baahan yahay 1575 ~ 1580nm), hadda shaqada ee wareegga TEC wuxuu u baahan yahay in la hagaajiyo, markaa in mawjadaha wax soo saarka si fiican loo xakameyn karo.
3. Natiijooyinka imtixaanka iyo falanqaynta
Tusayaasha tijaabada ah ee ugu weyn ee 10G EPON symmetric OLT moduleka indhaha waxaa ka mid ah waqtiga dejinta qaataha, dareenka qaataha, iyo gudbinta jaantuska indhaha.Tijaabooyin gaar ah waa sida soo socota:
(1) Hel waqtiga dejinta
Marka la eego jawiga shaqada caadiga ah ee kor u kicinta awoodda indhaha ee -24.0 dBm, ishaarka indhaha ee ka soo baxaya isha iftiinka dillaacay ayaa loo isticmaalaa sidii goobta cabbirka, iyo moduleku wuxuu helayaa oo dejiyaa calaamad koronto oo dhammaystiran sida barta dhamaadka cabbirka, iyadoo la iska indho tiray wakhtiga daahitaanka iftiinka ee fiilada tijaabadawakhtiga dejinta soo dhawaynta dilaaca 10G waa 241.8 ns, kaas oo waliba la kulma heerka caalamiga ah ee <800 ns.
3. Natiijooyinka imtixaanka iyo falanqaynta
Tusayaasha tijaabada ah ee ugu weyn ee 10G EPON symmetric OLT moduleka indhaha waxaa ka mid ah waqtiga dejinta qaataha, dareenka qaataha, iyo gudbinta jaantuska indhaha.Tijaabooyin gaar ah waa sida soo socota:
(1) Hel waqtiga dejinta
Marka la eego jawiga shaqada caadiga ah ee kor u kicinta awoodda indhaha ee -24.0 dBm, ishaarka indhaha ee ka soo baxaya isha iftiinka dillaacay ayaa loo isticmaalaa sidii goobta cabbirka, iyo moduleku wuxuu helayaa oo dejiyaa calaamad koronto oo dhammaystiran sida barta dhamaadka cabbirka, iyadoo la iska indho tiray daahitaanka wakhtiga iftiinka ee fiber-ka tijaabada ah.Qiyaasta 1G ee soo dhawaynta dilaaca wakhtiga dejinta waa 76.7 ns, kaas oo buuxiya heerka caalamiga ah ee <400 ns;wakhtiga dejinta soo dhawaynta dilaaca 10G waa 241.8 ns, kaas oo waliba la kulma heerka caalamiga ah ee <800 ns.
