Kwinkqubo ye-EPON, i-OLT idityaniswe kwii-ONU ezininzi (iiyunithi zenethiwekhi ye-optical) nge-POS (i-passive optical splitter).Njengondoqo we-EPON, iimodyuli ze-OLT ze-optical ziya kuchaphazela ngokuthe ngqo ukusebenza kwayo yonke inkqubo ye-EPON ye-10G.
1.Intshayelelo kwi-10G EPON imodyuli ye-OLT ye-symmetrical optical module
Imodyuli ye-OLT ye-10G ye-symmetrical OLT isebenzisa i-uplink burst reception kunye ne-downlink eqhubekayo yokuhambisa iindlela, ezisetyenziselwa ukuguqulwa kombane / ukuguqulwa kombane kwiinkqubo ze-EPON ze-10G.
Inxalenye yokufumana iquka i-TIA (i-transimpedance amplifier), i-APD (i-Avalanche Photodiode) kwi-1270 / 1310nm, kunye ne-LA ezimbini (i-amplifiers ezinciphisa) kwi-1.25 kunye ne-10.3125 Gbit / s rates.
Isiphelo sokudlulisa siqulunqwe nge-10G EML (i-electro-absorption modulation laser) kunye ne-1.25 Gbit / s DFB (i-laser ye-feedback esasazwayo), kunye ne-wavelengths yayo yokukhutshwa yi-1577 kunye ne-1490nm, ngokulandelanayo.
Umjikelezo wokuqhuba uquka i-digital APC (i-Automatic Optical Power Control) kunye ne-TEC (i-Temperature Compensation) isiphaluka sokugcina i-10G laser emission wavelength ezinzileyo.Ukujongwa kweparameter yokudlulisa kunye nokufumana iphunyezwa yi-microcomputer ye-chip enye ngokwe-SFF-8077iv4.5 protocol.
Ngenxa yokuba isiphelo sokufumana imodyuli ye-OLT ye-optical isebenzisa i-burst reception, ixesha lokusetha ukwamkela kubaluleke kakhulu.Ukuba ulwamkelo lokuhlala ixesha elide, luya kuchaphazela kakhulu uvakalelo, kwaye lunokubangela ukuba ulwamkelo oluqhumayo lungasebenzi kakuhle.Ngokweemfuno zeprotocol ye-IEEE 802.3av, ixesha lokusekwa kwe-1.25Gbit / s i-burst reception kufuneka ibe <400 ns, kwaye uvakalelo lokufumana ukuqhuma kufuneka lube <-29.78 dBm kunye nesantya esincinci se-10-12;kunye ne-10.3125 Gbit / s Ixesha lokumisa ukwamkela ngokugqabhuka kufuneka libe <800ns, kwaye uvakalelo lokwamkela ngokugqabhuka lube <-28.0 dBm ngesantya esincinci sempazamo ye-10-3.
I-2.10G i-EPON ye-symmetrical OLT yoyilo lwemodyuli ye-optical
2.1 Iskimu soyilo
Imodyuli ye-OLT ye-10G ye-symmetrical ye-OLT yenziwe nge-triplexer (i-fiber enye-modyuli yeendlela ezintathu), ukuhambisa, ukufumana, kunye nokubeka iliso.I-triplexer ibandakanya iilaser ezimbini kunye ne-detector.Ukukhanya okugqithisiweyo kunye nokukhanya okufunyenweyo kuhlanganiswe kwisixhobo se-optical ngokusebenzisa i-WDM (i-Wavelength Division Multiplexer) ukufezekisa i-fiber-fiber bidirectional transmission.Ukwakhiwa kwayo kuboniswe kuMfanekiso 1.
Inxalenye yokudlulisa iqulethe i-laser ezimbini, umsebenzi wayo oyintloko kukuguqula i-1G kunye ne-10G izibonakaliso zombane kwizibonakaliso ze-optical, ngokulandelanayo, kunye nokugcina ukuqina kwamandla okukhanya kwimeko evaliweyo ye-loop ngokusebenzisa i-digital APC circuit.Ngexesha elifanayo, i-microcomputer ye-single-chip ilawula ubukhulu bemodyuli yangoku ukufumana umlinganiselo wokuphela ofunekayo yinkqubo.Isekethe ye-TEC yongezwa kwi-10G yokuhambisa isiphaluka, esizinzisa kakhulu i-wavelength ye-laser ye-10G.Inxalenye efumanayo isebenzisa i-APD ukuguqula isignali ye-optical echongiweyo kwi-signal yombane, kwaye ikhuphe emva kokukhulisa kunye nokubunjwa.Ukuze kuqinisekiswe ukuba uvakalelo lunokufikelela kuluhlu olufanelekileyo, kuyimfuneko ukubonelela ngoxinzelelo oluphezulu oluzinzileyo kwi-APD kumaqondo okushisa ahlukeneyo.Ikhompyuter enye-chip ifezekisa le njongo ngokulawula i-APD high-voltage circuit.
2.2 Ukuphunyezwa kolwamkelo lweereyithi ezimbini zokugqabhuka
Inxalenye efumanayo ye-10G EPON imodyuli ye-OLT ye-optical symmetric isebenzisa indlela yokufumana ukuqhuma.Idinga ukufumana izibonakaliso zokugqabhuka kweereyithi ezimbini ezahlukeneyo ze-1.25 kunye ne-10.3125 Gbit / s, efuna ukuba inxalenye efumanayo ikwazi ukwahlula imiqondiso ye-optical yala mareyithi amabini ahlukeneyo kakuhle ukuze ufumane izibonakaliso zombane ezizinzileyo.Izikimu ezibini zokuphumeza ulwamkelo oluphindwe kabini lokuqhambuka kweemodyuli ze-OLT zokukhanya ziyacetywa apha.
Ngenxa yokuba isignali ye-optical input isebenzisa iteknoloji ye-TDMA (iCandelo leXesha lokuFikelela okuninzi), isantya esinye kuphela sokukhanya okugqabhukileyo sinokubakho ngexesha elinye.Isignali yegalelo inokuhlukaniswa kwi-domain optical ngokusebenzisa i-1: 2 i-splitter ye-optical, njengokuba iboniswe kwi-Figure 2. Okanye sebenzisa kuphela i-detector ye-high-speed detector ukuguqula i-1G kunye ne-10G izibonakaliso ze-optical zibe iimpawu zombane ezibuthathaka, kwaye emva koko uhlukanise ezimbini zombane. Iimpawu ezinamaqondo ahlukeneyo ngokusebenzisa i-TIA ye-bandwidth enkulu, njengoko kubonisiwe kuMfanekiso 3.
Iskimu sokuqala esiboniswe kuMzobo 2 siya kuzisa ukulahlekelwa okuthile kokufaka xa ukukhanya kudlula kwi-1: 2 i-splitter ye-optical, ekufuneka ikhulise isignali ye-optical input, ngoko ke i-amplifier optical ifakwe phambi kwe-splitter optical.Iisignali zamehlo ezahlukanisiweyo emva koko ziphantsi koguqulo lwe-optical / umbane ngabachongi bemilinganiselo eyahlukeneyo, kwaye ekugqibeleni iintlobo ezimbini zeziphumo zombane ezizinzileyo zifunyenwe.Ukungalungi okukhulu kwesi sisombululo kukuba i-amplifier optical kunye ne-1: i-2 optical splitter isetyenzisiweyo, kwaye ii-detectors ezimbini zifunekayo ukuguqula umqondiso we-optical, okwandisa ubunzima bokuphunyezwa kunye nokwandisa iindleko.
Kwiskimu sesibini esiboniswe kwi-FIG.I-3, i-input optical signal idinga kuphela ukudlula kwi-detector kunye ne-TIA ukufezekisa ukuhlukana kwi-domain yombane.Ingundoqo yesi sisombululo ixhomekeke ekukhethweni kwe-TIA, efuna i-TIA ibe ne-bandwidth ye-1 ~ 10Gbit / s, kwaye ngexesha elifanayo i-TIA inempendulo ekhawulezayo ngaphakathi kwesi sixhobo.Kuphela ngeparameter yangoku ye-TIA inokufumana ixabiso lempendulo ngokukhawuleza, ukuva ukuva kunokuqinisekiswa kakuhle.Esi sisombululo sinciphisa kakhulu ubunzima bokuphunyezwa kwaye sigcina iindleko ziphantsi kolawulo.Kuyilo lokwenyani, sikhetha ngokubanzi iskimu sesibini ukuphumeza ulwamkelo lokuqhambuka kabini.
2.3 Uyilo lwesekethe yehardware ekupheleni kokwamkela
Umzobo we-4 yisekethe ye-hardware yecandelo eliqhekezayo elifumanayo.Xa kukho igalelo eliqhumayo, i-APD iguqula isignali ye-optical ibe ngumqondiso obuthathaka wombane kwaye uyithumele kwi-TIA.Umqondiso ukhuliswa yi-TIA kwi-10G okanye i-1G yombane yombane.I-10G yombane yombane igalelo kwi-10G LA ngokudibanisa okulungileyo kwe-TIA, kunye ne-1G yombane yombane ifakwe kwi-1G LA ngokusebenzisa ukudibanisa okungalunganga kwe-TIA.I-Capacitors i-C2 kunye ne-C3 i-coupling capacitors esetyenziselwa ukufezekisa i-10G kunye ne-1G imveliso edibeneyo ye-AC.Indlela edityanisiweyo ye-AC yakhethwa kuba ilula kunendlela edityanisiweyo ye-DC.
Nangona kunjalo, ukudibanisa kwe-AC kunomrhumo kunye nokukhutshwa kwe-capacitor, kwaye isantya sokuphendula kwisignali sichaphazeleka ngokuhlawulwa kunye nexesha lokukhupha rhoqo, oko kukuthi, umqondiso awukwazi ukuphendulwa ngexesha.Olu phawu lubophelelekile ukuba ulahlekelwe yimali ethile yokufumana ixesha lokuhlala, ngoko ke kubalulekile ukukhetha ukuba inkulu kangakanani i-AC coupling capacitor.Ukuba i-coupling capacitor encinci ikhethiwe, ixesha lokumisa lingafinyezwa, kwaye umqondiso ohanjiswe yi-ONU kwixesha ngalinye unokufunyanwa ngokupheleleyo ngaphandle kokuchaphazela umphumo wokwamkela ngenxa yokuba ixesha lokumisa ukwamkela lide kakhulu kwaye ukufika kwexesha elizayo. slot.
Nangona kunjalo, i-capacitance encinci iya kuchaphazela umphumo wokudibanisa kunye nokunciphisa kakhulu ukuzinza kokufumana.I-capacitance enkulu inokunciphisa i-jitter yenkqubo kwaye iphucule uvakalelo lwesiphelo sokufumana.Ngoko ke, ukwenzela ukuba kuthathelwe ingqalelo i-reception yokumisa ixesha kunye ne-reception sensitivity, i-coupling capacitors efanelekileyo i-C2 kunye ne-C3 kufuneka ikhethwe.Ukongezelela, ukwenzela ukuba kuqinisekiswe ukuzinza kwesignali yombane, i-coupling capacitor kunye ne-resistor ehambelanayo kunye nokumelana ne-50Ω ixhunyiwe kwi-terminal engafanelekanga ye-LA.
I-LVPECL (i-Low Voltage Positive Emitter Coupling Logic) isekethe eyenziwe ngabaxhathisi i-R4 kunye ne-R5 (i-R6 kunye ne-R7) kunye ne-2.0 V yomthombo wombane we-DC ngokuphuma kwesignali eyahlukileyo nge-10G (1G) LA.uphawu lombane.
2.4 Icandelo lokwazisa
Inxalenye yokudlulisa ye-10G EPON i-symmetric OLT imodyuli ye-optical ihlulwe ngokukodwa kwiindawo ezimbini ze-1.25 kunye ne-10G yokudlulisa, ngokulandelanayo ukuthumela iimpawu kunye nobude be-1490 kunye ne-1577 nm kwi-downlink.Ukuthatha inxalenye yokudlulisa i-10G njengomzekelo, ibini leempawu ze-10G ezihlukeneyo zingena kwi-chip ye-CDR (i-Clock Shaping), i-AC-idibene ne-chip ye-10G yomqhubi, kwaye ekugqibeleni igalelo elihlukeneyo kwi-laser ye-10G.Ngenxa yokuba utshintsho lweqondo lokushisa luya kuba nefuthe elikhulu kwi-laser emission wavelength, ukwenzela ukuzinzisa ubude be-wavelength ukuya kwinqanaba elifunwa yiprotocol (iprotocol ifuna i-1575 ~ 1580nm), ukusebenza kwangoku kwesekethe ye-TEC kufuneka kulungiswe, ngoko ke. ukuba i-wavelength yemveliso inokulawulwa kakuhle.
3. Iziphumo zovavanyo kunye nohlalutyo
Iimpawu eziphambili zovavanyo ze-10G EPON imodyuli ye-OLT ye-optical ye-symmetric iquka ixesha lokumisela ummkeli, ukuvakalelwa kommkeli, kunye nokudlulisa umzobo wamehlo.Iimvavanyo ezithile zezi zilandelayo:
(1) Fumana ixesha lokucwangcisa
Ngaphantsi kwendawo eqhelekileyo yokusebenza ye-uplink burst optical power -24.0 dBm, isignali ye-optical ekhutshwe ngumthombo wokukhanya ogqabhukileyo isetyenziswe njengendawo yokulinganisa isiqalo, kwaye imodyuli ifumana kwaye imise umqondiso opheleleyo wombane njengendawo yokuphela komlinganiselo, ungayihoyi ukulibaziseka kwexesha lokukhanya kwi-fiber yokuvavanya.Ixesha lokumisela i-1G burst reception reception yi-76.7 ns, edibana nomgangatho wamazwe ngamazwe <400 ns;i-10G ukuqhuma kwexesha lokumisa ukwamkelwa yi-241.8 ns, ekwadibana nomgangatho wamazwe ngamazwe <800 ns.
3. Iziphumo zovavanyo kunye nohlalutyo
Iimpawu eziphambili zovavanyo ze-10G EPON imodyuli ye-OLT ye-optical ye-symmetric iquka ixesha lokumisela ummkeli, ukuvakalelwa kommkeli, kunye nokudlulisa umzobo wamehlo.Iimvavanyo ezithile zezi zilandelayo:
(1) Fumana ixesha lokucwangcisa
Ngaphantsi kwendawo eqhelekileyo yokusebenza ye-uplink burst optical power -24.0 dBm, isignali ye-optical ekhutshwe ngumthombo wokukhanya ogqabhukileyo isetyenziswe njengendawo yokulinganisa isiqalo, kwaye imodyuli ifumana kwaye imise umqondiso opheleleyo wombane njengendawo yokuphela komlinganiselo, ungayihoyi ukulibaziseka kwexesha lokukhanya kwifiber yovavanyo.Ixesha elilinganiselweyo le-1G lokuqhawula ukwamkelwa kwe-reception yi-76.7 ns, ehlangabezana nomgangatho wamazwe ngamazwe <400 ns;i-10G ukuqhuma kwexesha lokumisa ukwamkelwa yi-241.8 ns, ekwadibana nomgangatho wamazwe ngamazwe <800 ns.
