Muchirongwa cheEPON, OLT yakabatana kune akawanda ONUs (optical network units) kuburikidza nePOS (passive optical splitter).Sezvo musimboti weEPON, OLT optical modules ichakanganisa zvakananga kushanda kwese 10G EPON system.
1.Introduction ku10G EPON symmetrical OLT optical module
Iyo 10G EPON symmetrical OLT optical module inoshandisa uplink burst reception uye downlink inoenderera mberi yekufambisa modhi, iyo inonyanya kushandiswa kushandurudza optical / magetsi mu10G EPON masisitimu.
Chikamu chinogashira chine TIA (transimpedance amplifier), APD (Avalanche Photodiode) pa1270 / 1310nm, uye maviri LA (anoderedza amplifiers) pa1.25 uye 10.3125 Gbit / s mitengo.
Magumo ekutumira anoumbwa ne10G EML (electro-absorption modulation laser) uye 1.25 Gbit / s DFB (yakagoverwa mhinduro laser), uye emission wavelengths i1577 uye 1490nm, zvichiteerana.
Dunhu rekutyaira rinosanganisira dhijitari APC (Automatic Optical Power Control) dunhu uye TEC (Temperature Compensation) dunhu rekuchengetedza yakagadzikana 10G laser emission wavelength.Iyo yekufambisa uye yekugashira paramende yekutarisa inoshandiswa neiyo imwechete chip microcomputer zvinoenderana neSFF-8077iv4.5 protocol.
Nekuti iyo yekugamuchira yekupedzisira yeOLT Optical module inoshandisa kuputika kwekugamuchira, iyo yekugashira yekugadzika nguva inonyanya kukosha.Kana iyo yekugashira kugadzirisa nguva yakareba, ichakanganisa zvakanyanya kunzwisiswa, uye inogona kutokonzera kuputika kugashira kusashanda zvakanaka.Zvinoenderana nezvinodiwa neIEEE 802.3av protocol, nguva yekugadzwa kwe1.25Gbit / s yakaputika reception inofanira kunge iri <400 ns, uye kuputika kwekunzwa kwekugamuchira kunofanira kunge kuri <-29.78 dBm nekamwe kukanganisa kwe10-12;uye 10.3125 Gbit / s Iyo yakaputika yekugashira nguva yekumisikidza inofanira kunge iri <800ns, uye kuputika kwekunzwa kwekugamuchira kunofanira kunge kuri <-28.0 dBm nekamwe kukanganisa kwe10-3.
2.10G EPON symmetrical OLT optical module design
2.1 Dhizaini chirongwa
Iyo 10G EPON symmetrical OLT optical module inoumbwa ne triplexer (single-fiber matatu-nzira module), kutumira, kugamuchira, uye kutarisa.Iyo triplexer inosanganisira maviri lasers uye detector.Chiedza chinoparidzirwa uye chiedza chakagamuchirwa chinosanganiswa muchigadzirwa chemaziso kuburikidza neWDM (Wavelength Division Multiplexer) kuti iwane imwe-fiber bidirectional transmission.Chimiro chayo chinoratidzwa mumufananidzo 1.
Chikamu chekutumira chinosanganisira maviri lasers, ayo basa guru nderokushandura 1G uye 10G zviratidzo zvemagetsi muzviratidzo zvemaziso, maererano, uye kuchengetedza simba remagetsi rakagadzikana mumhepo yakavharwa yakavharwa kuburikidza ne digital APC circuit.Panguva imwecheteyo, iyo single-chip microcomputer inodzora ukuru hweiyo modulation ikozvino kuti iwane chiyero chekudzima chinodiwa nehurongwa.Dunhu reTEC rinowedzerwa kune 10G yekufambisa dunhu, iyo inodzikamisa zvakanyanya kubuda kwewavelength ye10G laser.Chikamu chinogashira chinoshandisa APD kushandura iyo yakaonekwa kuputika chiratidzo chemagetsi kuita chiratidzo chemagetsi, uye inoiburitsa mushure mekusimudzira uye kuumbwa.Kuti uve nechokwadi chekuti senitivity inogona kusvika kune yakanakira siyana, zvinodikanwa kupa yakagadzika kudzvanywa kwepamusoro kune APD pane tembiricha dzakasiyana.Iyo imwe-chip komputa inozadzisa chinangwa ichi nekudzora iyo APD yakakwira-voltage wedunhu.
2.2 Kuitwa kwehuviri-chiyero chekuputika kwekugamuchira
Chikamu chekugamuchira che10G EPON symmetric OLT optical module inoshandisa nzira yekugamuchira kuputika.Inoda kugashira masaini ekuputika kwemazinga maviri akasiyana e1.25 uye 10.3125 Gbit / s, izvo zvinoda kuti chikamu chinogashira chikwanise kusiyanisa masaini emaziso eaya mareti maviri akasiyana zvakanaka kuitira kuwana yakagadzikana inobuda masaini emagetsi.Zvirongwa zviviri zvekushandisa mbiri-chiyero kuputika kugashira kweOLT optical modules zvinokurudzirwa pano.
Nekuti iyo yekuisa yekuona chiratidzo inoshandisa tekinoroji yeTDMA (Nguva Yekugovera Multiple Access), chiyero chimwe chete chechiedza chinoputika chinogona kuvapo panguva imwe chete.Chiratidzo chekupinza chinogona kuparadzaniswa munharaunda ye optical kuburikidza ne1: 2 optical splitter, seyakaratidzwa mumufananidzo 2. Kana kuti shandisa chete high-speed detector kuti uchinje 1G uye 10G zviratidzo zvemaziso mumagetsi asina simba, uye wozoparadzanisa magetsi maviri emagetsi. masaini ane mareti akasiyana kuburikidza neyakakura bandwidth TIA, sezvakaratidzwa mumufananidzo 3.
Chirongwa chekutanga chinoratidzwa muMufananidzo 2 chichaunza kumwe kurasikirwa kwekuisa kana chiedza chichipfuura nepakati pe 1: 2 optical splitter, iyo inofanira kukwidziridza chiratidzo chekupinza chemaziso, saka an optical amplifier inoiswa pamberi pe optical splitter.Iwo akapatsanurwa optical masaini anobva aiswa pasi pekuona / kushandurwa kwemagetsi nema detectors emitengo yakasiyana, uye pakupedzisira marudzi maviri eakagadzikana emagetsi masaini anobuda anowanikwa.Kunyanya kukanganisa kweiyi mhinduro ndeyokuti optical amplifier uye 1: 2 optical splitter inoshandiswa, uye ma detector maviri anodiwa kuti ashandure chiratidzo chemaziso, izvo zvinowedzera kuoma kwekushandiswa uye kuwedzera mari.
Muchirongwa chechipiri chinoratidzwa muFIG.3, iyo yekuisa chiratidzo chemaziso inongoda kupfuura ne detector uye TIA kuti iwane kupatsanurwa munzvimbo yemagetsi.Nheyo yemhinduro iyi iri mukusarudzwa kweTIA, iyo inoda kuti TIA ive nebandwidth ye1 ~ 10Gbit / s, uye panguva imwechete TIA ine mhinduro inokurumidza mukati meiyi bandwidth.Chete kuburikidza neazvino parameter yeTIA inogona kuwana kukosha kwekupindura nekukurumidza, iyo yekugamuchira senitivity inogona kunyatso vimbiswa.Iyi mhinduro inoderedza zvakanyanya kuoma kwekuita uye inochengeta mari iri pasi pekutonga.Mumagadzirirwo chaiwo, isu tinowanzo sarudza yechipiri chirongwa kuti tiwane mbiri-chiyero kuputika kwekugamuchira.
2.3 Dhizaini yedunhu rehardware pakupera kwekugamuchira
Fig. 4 ndiyo hardware circuit yechikamu chinoputika chekugamuchira.Kana paine kuputika kwekupinza kwemaziso, iyo APD inoshandura chiratidzo chemaziso kuita chiratidzo chisina simba chemagetsi uye chinotumira kuTIA.Chiratidzo chinokwidziridzwa neTIA kuita 10G kana 1G chiratidzo chemagetsi.Chiratidzo chemagetsi che10G chinoiswa ku10G LA kuburikidza nekubatana kwakanaka kweTIA, uye chiratidzo chemagetsi che1G chinoiswa ku1G LA kuburikidza nekubatana kusina kunaka kweTIA.Capacitors C2 uye C3 ari kubatanidza capacitors anoshandiswa kuwana 10G uye 1G AC-yakabatana kubuda.Iyo AC-yakabatana nzira yakasarudzwa nekuti iri nyore pane iyo DC-yakabatana nzira.
Zvisinei, iyo AC coupling ine mutero uye kubudiswa kwe capacitor, uye kukurumidza kwekupindura kune chiratidzo kunobatwa nechaji uye kuburitsa nguva nguva dzose, ndiko kuti, chiratidzo hachigoni kupindurwa munguva.Ichi chimiro chinosungirwa kurasikirwa nehumwe huwandu hwekugamuchira kugadzirisa nguva, saka zvakakosha kusarudza kuti yakakura sei iyo AC coupling capacitor.Kana iyo diki coupling capacitor yakasarudzwa, nguva yekugadzirisa inogona kupfupikiswa, uye chiratidzo chinofambiswa neONU mune imwe neimwe nguva slot inogona kugamuchirwa zvachose pasina kukanganisa maitiro ekugamuchira nekuti nguva yekugashira yekugashira yakarebesa uye nekuuya kwenguva inotevera. slot.
Nekudaro, yakawandisa capacitance ichakanganisa iyo coupling mhedzisiro uye inoderedza zvakanyanya kugadzikana kwekugamuchira.Yakakura capacitance inogona kuderedza jitter system uye kugadzirisa kunzwisiswa kwekupedzisira kwekugamuchira.Nokudaro, kuitira kuti tifunge nezvekugamuchira kugadzika nguva uye kunzwisiswa kwekugamuchira, zvakakodzera coupling capacitors C2 neC3 inoda kusarudzwa.Mukuwedzera, kuitira kuti uve nechokwadi chekugadzikana kwechiratidzo chemagetsi chekupinza, coupling capacitor uye inopikisa inopikisa ine kupesana kwe50Ω yakabatanidzwa kune yakaipa terminal ye LA.
LVPECL (Low Voltage Positive Emitter Coupling Logic) dunhu rinoumbwa neresistors R4 neR5 (R6 neR7) uye 2.0 V DC voltage sosi kuburikidza nekusiyanisa chiratidzo chinobuda ne10G (1G) LA.chiratidzo chemagetsi.
2.4 Kuvhura chikamu
Chikamu chekutumira che10G EPON symmetric OLT optical module inonyanya kukamurwa kuita zvikamu zviviri zve 1.25 uye 10G kutumira, izvo zvinotumira zvikwangwani zvine wavelength ye1490 uye 1577 nm kune downlink.Kutora chikamu chekutumira 10G semuenzaniso, peya ye10G yekusiyanisa masaini inopinda muCDR (Clock Shaping) chip, iri AC-yakabatana kune 10G mutyairi chip, uye pakupedzisira inopinda zvakasiyana mu10G laser.Nekuti shanduko yetembiricha ichave nepesvedzero huru pane laser emission wavelength, kuitira kudzikamisa wavelength kusvika padanho rinodiwa neprotocol (iyo protocol inoda 1575 ~ 1580nm), kushanda ikozvino kweTEC dunhu kunoda kugadziriswa, saka kuti iyo yakabuda wavelength inogona kudzorwa zvakanaka.
3. Migumisiro yekuedza uye kuongorora
Iyo mikuru yekuyedza zviratidzo zve10G EPON symmetric OLT optical module inosanganisira iyo inogamuchira yekugadzika nguva, yekugamuchira senitivity, uye kutumira dhizaini yeziso.Iwo chaiwo bvunzo ndeokuti:
(1) Gamuchira nguva yekuseta
Pasi penzvimbo yakajairika yekushanda yeuplink burst optical power ye -24.0 dBm, chiratidzo chemaziso chinobudiswa nechiedza chinoputika chinoshandiswa seyero yekutangira, uye module inogamuchira uye inogadza chiratidzo chemagetsi chakazara seyero yekupedzisira, tichiregeredza nguva kunonoka kwechiedza mufiber yekuedza.Iyo yakayerwa 1G yakaputika reception setup time is 76.7 ns, iyo inosangana nenyika dzepasi rose <400 ns;iyo 10G yakaputika reception setup time is 241.8 ns, iyo inosanganawo nehuwandu hwepasi rose hwe <800 ns.
3. Migumisiro yekuedza uye kuongorora
Iyo mikuru yekuyedza zviratidzo zve10G EPON symmetric OLT optical module inosanganisira iyo inogamuchira yekugadzika nguva, yekugamuchira senitivity, uye kutumira dhizaini yeziso.Iwo chaiwo bvunzo ndeokuti:
(1) Gamuchira nguva yekuseta
Pasi penzvimbo yakajairika yekushanda yeuplink burst optical power ye -24.0 dBm, chiratidzo chemaziso chinobudiswa nechiedza chinoputika chinoshandiswa seyero yekutangira, uye module inogamuchira uye inogadza chiratidzo chemagetsi chakazara seyero yekupedzisira, tichiregeredza nguva kunonoka kwechiedza muyedzo fiber.Iyo yakayerwa 1G burst reception setup time is 76.7 ns, iyo inosangana nenyika dzepasi rose dze <400 ns;iyo 10G yakaputika reception setup time is 241.8 ns, iyo inosanganawo nehuwandu hwepasi rose hwe <800 ns.
