Lenaneong la EPON, OLT e hokahane le li-ONU tse ngata (optical network units) ka POS (passive optical splitter).E le motheo oa EPON, OLT optical modules e tla ama ka ho toba ts'ebetsong ea tsamaiso eohle ea 10G EPON.
1.Selelekela ho 10G EPON symmetrical OLT optical module
The 10G EPON symmetrical OLT optical module e sebelisa uplink burst reception le downlink e tsoelang pele mekhoa ea phetisetso, e sebelisoang haholo-holo bakeng sa phetoho ea optical / motlakase ho 10G EPON systems.
Karolo e amohelang e na le TIA (transimpedance amplifier), APD (Avalanche Photodiode) ho 1270 / 1310nm, le tse peli LA (li-amplifiers tse fokotsang) ho 1.25 le 10.3125 Gbit / s litekanyetso.
Qetello ea phetisetso e entsoe ka 10G EML (electro-absorption modulation laser) le 1.25 Gbit / s DFB (laser ea maikutlo e ajoang), 'me maqhubu a eona a hlahisoang ke 1577 le 1490nm, ka ho latellana.
Potoloho ea ho khanna e kenyelletsa potoloho ea digital APC (Automatic Optical Power Control) le potoloho ea TEC (Temperature Compensation) bakeng sa ho boloka sebaka se tsitsitseng sa 10G laser emission wavelength.Tlhokomelo ea paramethara ea ho fetisa le ho amohela e sebelisoa ke microcomputer e le 'ngoe ho latela protocol ea SFF-8077iv4.5.
Hobane pheletso e amohelang ea OLT optical module e sebelisa kamohelo e phatlohileng, nako ea ho seta ea kamohelo e bohlokoa haholo.Haeba nako ea kamohelo ea kamohelo e le telele, e tla ama maikutlo a mangata haholo, 'me e ka ba ea etsa hore kamohelo e phatlohileng e se ke ea sebetsa hantle.Ho ea ka litlhoko tsa protocol ea IEEE 802.3av, nako ea ho thehoa ha 1.25Gbit / s burst reception e tlameha ho ba <400 ns, 'me ho phatloha ho hoholo hoa maikutlo ho tlameha ho ba <-29.78 dBm ka sekhahla sa phoso ea 10-12;le 10.3125 Gbit / s Nako ea ho qala kamohelo e phatlohileng e tlameha ho ba <800ns, 'me kutloisiso ea ho amohela ho phatloha e tlameha ho ba <-28.0 dBm ka sekhahla sa phoso ea 10-3.
2.10G EPON moralo oa symmetrical OLT optical module
2.1 Sekema sa moralo
The 10G EPON symmetrical OLT optical module e entsoe ka triplexer (single-fiber three-way module), ho fetisa, ho amohela, le ho hlahloba.Triplexer e kenyelletsa lasers tse peli le detector.Leseli le fetisitsoeng le leseli le amohetsoeng li kenyelelitsoe mochine oa optical ka WDM (Wavelength Division Multiplexer) ho finyella phetisetso ea bidirectional e le 'ngoe ea fiber.Sebopeho sa eona se bontšitsoe setšoantšong sa 1.
Karolo ea ho fetisa e na le li-lasers tse peli, tseo mosebetsi oa tsona o ka sehloohong e leng ho fetola lipontšo tsa motlakase tsa 1G le 10G ka lipontšo tsa optical, ka ho latellana, le ho boloka botsitso ba matla a optical sebakeng se koetsoeng sa loop ka potoloho ea digital APC.Ka nako e ts'oanang, microcomputer e le 'ngoe e laola boholo ba hona joale ea modulation ho fumana karolelano ea ho timela e hlokoang ke tsamaiso.Potoloho ea TEC e eketsoa ho potoloho ea 10G e fetisang, e tsitsisang haholo bolelele ba maqhubu a laser ea 10G.Karolo e amohelang e sebelisa APD ho fetolela lets'oao la optical le bonoeng hore e be lets'oao la motlakase, ebe le le hlahisa kamora ho holisoa le ho bopa.E le ho etsa bonnete ba hore kutloisiso e ka fihla boemong bo loketseng, ho hlokahala ho fana ka khatello e phahameng e tsitsitseng ho APD ka mocheso o fapaneng.Khomphuta e le 'ngoe e finyella pakane ena ka ho laola potoloho e phahameng ea APD.
2.2 Phethahatso ea kamohelo ea sekhahla se habeli
Karolo e amohelang ea 10G EPON symmetric OLT optical module e sebelisa mokhoa o phatlohileng oa ho amohela.E hloka ho amohela matšoao a phatlohileng a litekanyetso tse peli tse fapaneng tsa 1.25 le 10.3125 Gbit / s, tse hlokang hore karolo e amohelang e khone ho khetholla matšoao a optical a litekanyetso tsena tse peli tse fapaneng hantle e le ho fumana matšoao a tsitsitseng a motlakase.Merero e 'meli ea ho kenya ts'ebetsong kamohelo ea li-dual-rate burst ea li-OLT Optical modules e hlahisoa mona.
Hobane lets'oao la optical la ho kenya le sebelisa theknoloji ea TDMA (Time Division Multiple Access), ho ka ba le sekhahla se le seng feela sa khanya e phatlohileng ka nako e le 'ngoe.Letšoao la ho kenya le ka aroloa sebakeng sa optical ka 1: 2 optical splitter, e kang E bontšitsoeng ho Setšoantšo sa 2. Kapa sebelisa mochine o lebelo le phahameng feela ho fetola matšoao a optical 1G le 10G hore e be lipontšo tsa motlakase tse fokolang, ebe o arola tse peli tsa motlakase. matšoao a nang le litefiso tse fapaneng ka TIA ea bandwidth e kholoanyane, joalo ka ha ho bonts'itsoe ho Setšoantšo sa 3.
Morero oa pele o bontšitsoeng ho Setšoantšo sa 2 o tla tlisa tahlehelo e itseng ea ho kenya ha leseli le feta 1: 2 optical splitter, e lokelang ho matlafatsa pontšo ea optical e kenang, kahoo amplifier ea optical e kenngoa ka pel'a sesepa sa optical.Lits'oants'o tse arohaneng tsa optical li ka fetoha phetoho ea optical / motlakase ke li-detectors tsa litekanyetso tse fapaneng, 'me qetellong ho fumanoa mefuta e' meli ea lipontšo tse tsitsitseng tsa motlakase.Bothata bo boholo ka ho fetisisa ba tharollo ena ke hore ho sebelisoa amplifier ea optical le 1: 2 optical splitter, 'me ho hlokahala lisebelisoa tse peli ho fetola pontšo ea optical, e leng ho eketsang ho rarahana ha ts'ebetsong le ho eketsa litšenyehelo.
Lenaneong la bobeli le bontšitsoeng ho FIG.3, lets'oao la optical input le hloka feela ho feta ka har'a detector le TIA ho fihlela karohano sebakeng sa motlakase.Moko oa tharollo ena ke khetho ea TIA, e hlokang hore TIA e be le bandwidth ea 1 ~ 10Gbit / s, 'me ka nako e ts'oanang TIA e na le karabelo e potlakileng ka har'a bandwidth ena.Ke feela ka paramente ea hajoale ea TIA e ka fumanang boleng ba karabelo kapele, kutloisiso e amohelang e ka netefatsoa hantle.Tharollo ena e fokotsa haholo ho rarahana ha ts'ebetsong le ho boloka litšenyehelo tlas'a taolo.Moqapi oa 'nete, ka kakaretso re khetha leano la bobeli ho fihlela kamohelo ea makhetlo a mabeli.
2.3 Moralo oa potoloho ea hardware qetellong ea ho amohela
Setšoantšo sa 4 ke potoloho ea hardware ea karolo e phatlohileng ea ho amohela.Ha ho e-na le ho phatloha ha optical input, APD e fetola letšoao la optical hore e be letšoao le fokolang la motlakase ebe le le romela ho TIA.Letšoao le matlafatsoa ke TIA hore e be letšoao la motlakase la 10G kapa 1G.Letšoao la motlakase la 10G le kenngoa ho 10G LA ka ho kopanya hantle ha TIA, 'me letšoao la motlakase la 1G le kenngoa ho 1G LA ka ho kopanya hampe ha TIA.Li-capacitor C2 le C3 ke li-capacitor tse kopanyang tse sebelisetsoang ho finyella 10G le 1G AC-coupled output.Mokhoa oa AC-coupled o khethiloe hobane o bonolo ho feta mokhoa oa DC-coupled.
Leha ho le joalo, ho kopanya ha AC ho na le tefiso le ho tsoa ha capacitor, 'me lebelo la karabo ho letšoao le angoa ke tefiso le nako ea ho qeta nako e sa khaotseng, ke hore, pontšo e ke ke ea arajoa ka nako.Tšobotsi ena e tlamehile ho lahleheloa ke nako e itseng ea ho amohela kamohelo, kahoo ke habohlokoa ho khetha hore na AC coupling capacitor e kholo hakae.Haeba ho khethoa capacitor e nyenyane ea ho kopanya, nako ea ho lokisa e ka khutsufatsoa, 'me pontšo e fetisitsoeng ke ONU ka nako e' ngoe le e 'ngoe e ka amoheloa ka ho feletseng ntle le ho ama phello ea kamohelo hobane nako ea ho amohela kamohelo e telele haholo le ho fihla ha nako e tlang. sekotjana.
Leha ho le joalo, capacitance e nyenyane haholo e tla ama phello ea ho kopanya 'me e fokotse haholo botsitso ba kamohelo.Capacitance e kholo e ka fokotsa jitter ea sistimi mme ea ntlafatsa kutlo ea pheletso e amohelang.Ka hona, e le hore u nahane ka nako ea ho amohela kamohelo le kutloisiso ea kamohelo, li-capacitor tse loketseng tsa ho kopanya C2 le C3 li hloka ho khethoa.Ho phaella moo, e le ho netefatsa botsitso ba pontšo ea motlakase oa ho kenya letsoho, coupling capacitor le resistor e ts'oanang le khanyetso ea 50Ω e amana le terminal e mpe ea LA.
Potoloho ea LVPECL (Low Voltage Positive Emitter Coupling Logic) e entsoeng ka li-resistor R4 le R5 (R6 le R7) le mohloli oa motlakase oa 2.0 V DC ka phallo ea matshwao a fapaneng ka 10G (1G) LA.lets'oao la motlakase.
2.4 Karolo ea ho qala
Karolo e fetisang ea 10G EPON symmetric OLT optical module e arotsoe haholo-holo likarolo tse peli tsa 1.25 le 10G transmitting, e leng ka ho latellana ho romellang lipontšo ka leqhubu la 1490 le 1577 nm ho theolela tlaase.Ho nka karolo ea phetisetso ea 10G e le mohlala, matšoao a fapaneng a 10G a kenya mochine oa CDR (Clock Shaping) chip, ke AC e kopantsoeng le mochine oa mokhanni oa 10G, 'me qetellong e kenngoa ka tsela e fapaneng ka laser 10G.Hobane phetoho ea mocheso e tla ba le tšusumetso e kholo ho leqhubu la laser emission wavelength, e le ho tsitsisa bolelele ba maqhubu ho isa boemong bo hlokoang ke protocol (protocol e hloka 1575 ~ 1580nm), ts'ebetso ea hona joale ea potoloho ea TEC e hloka ho lokisoa, kahoo. hore wavelength e hlahisoang e ka laoloa hantle.
3. Liphetho tsa liteko le tlhahlobo
Matšoao a mantlha a tlhahlobo ea 10G EPON symmetric OLT optical module e kenyelletsa nako ea ho seta ea moamoheli, kutlo ea moamoheli, le sets'oants'o sa mahlo se fetisang.Liteko tse khethehileng ke tse latelang:
(1) Fumana nako ea ho seta
Tlas'a tikoloho e tloaelehileng ea ts'ebetso ea uplink burst optical power ea -24.0 dBm, lets'oao la optical le hlahisoang ke mohloli oa leseli le phatlohileng le sebelisoa e le tekanyo ea ho qala, 'me mojule o amohela le ho theha lets'oao le felletseng la motlakase joalo ka ntlha ea ho lekanya, ho hlokomoloha nako ea ho lieha ha leseli ka faeba ea teko. Nako e lekantsoeng ea 1G burst reception setup ke 76.7 ns, e kopanang le maemo a machaba a <400 ns;nako ea ho seta ea ho amohela 10G e phatloha ke 241.8 ns, eo hape e kopanang le maemo a machaba a <800 ns.
3. Liphetho tsa liteko le tlhahlobo
Matšoao a mantlha a tlhahlobo ea 10G EPON symmetric OLT optical module e kenyelletsa nako ea ho seta ea moamoheli, kutlo ea moamoheli, le sets'oants'o sa mahlo se fetisang.Liteko tse khethehileng ke tse latelang:
(1) Fumana nako ea ho seta
Tlas'a tikoloho e tloaelehileng ea ts'ebetso ea uplink burst optical power ea -24.0 dBm, lets'oao la optical le hlahisoang ke mohloli oa leseli le phatlohileng le sebelisoa e le tekanyo ea ho qala, 'me mojule o amohela le ho theha lets'oao le felletseng la motlakase joalo ka ntlha ea ho lekanya, ho hlokomoloha nako ea ho lieha ha leseli ka har'a fiber ea teko.Nako e lekantsoeng ea 1G burst reception setup ke 76.7 ns, e kopanang le maemo a machaba a <400 ns;nako ea ho seta ea ho amohela 10G e phatloha ke 241.8 ns, eo hape e kopanang le maemo a machaba a <800 ns.
