Deployment analysis of TDM/WDM single fiber PON with colourless ONU operating at 2.5 Gbps subcarrier multiplexed downstream and 1.25 gbps upstream

Deploymen analysis o TDM/WDM Single Fibe PON wi h Colou less ONU Ope a ing a 2.5 Gbps Subca ie Mul iplexed Downs eam and 1.25 Gbps Ups eam Josep M. Fab ega 1 , membe OSA, Ahmad El Ma dini 2 , Vic o Polo 1 , José A. Láza o 1 , membe OSA, Edua do T. Lopez 1 , Ris o Soila 2 , and Josep P a 1 , membe OSA (1) Uni e si a Poli ècnica de Ca alunya (UPC), Dep . Signal Theo y and Communica ions, Jo di Gi ona 1, D4-D5, 08034 Ba celona (Spain). E-mail: jm ab ega@ sc.upc.edu (2) Tellabs Inc., 18581 Dallas Pa kway. Dallas, TX 75287 U.S.A E-mail: ahmad.elma dini@ ellabs.com Abs ac : A single- ibe ull-duplex hyb id TDM/WDM-PON is demons a ed o ope a e a 2.5/1.25 Gbps a es, wi h RSOA ONU. I achie es high powe budge (GPON complian ) a a dis ances highe han 20km, and se es up o 1280 use s. OCIS codes: (060.4510) Op ical communica ions, (060.4250) Op ical ne wo ks. 1. In oduc ion Access Passi e Op ical Ne wo ks (PONs) ha e eme ged as e ec i e pla o ms o deploy bandwid h demanding ad anced se ices. Thus, nex gene a ion PONs ha e o sol e se e al challenges, including high bi a e deli e ing and Wa eleng h Di ision Mul iplexing (WDM). A manda o y speci ica ion is he use o a single ibe o bo h, ups eam and downs eam ansmission, o educe he size o he ex e nal plan and he complexi y o he Op ical Ne wo k Uni (ONU). Ano he in e es ing ea u e is he use o he same wa eleng h o ups eam and downs eam senses, un es ic ing he wa eleng h’s use, and leading o he use o e lec i e colou less ONUs. In he pas , some ad anced designs which a oid he gene a ion o ligh a he ONU by using di e en modula ion schemes o downlink and uplink ansmission ha e been demons a ed [1-2]. Howe e , hese me hods may no be low-cos , due o he componen s needed o modula ion and de ec ion o he up/downs eam signals. A mo e cos -e ec i e solu ion can be he use o a subca ie mul iplex (SCM) echnique [3-4]. Using his echnique ups eam and downs eam spec ums a e no o e lapped, and he sys em becomes mo e ole an in on o Rayleigh backsca e ing. In his pape , o he i s ime, we demons a e a 20 km ull duplex PON ope a ing a a a e o 2.5 Gbps downs eam and 1.25 Gbps ups eam using he SCM echnique, gi ing se ice o a maximum o 1280 use s. Aiming o each he use wi h single ibe -scheme, he ole ance agains Rayleigh backsca e ing a ios is also e alua ed. 2. Expe imen s and discussion The Op ical Line Te minal (OLT) and ONU schemes o es a e depic ed in Fig. 1. Fo he 2.5 Gbps downs eam signal we used a Mach-Zehnde Modula o (MZM) p eceded by a lase (ope a ing a 1550.12 nm), and ollowed by an EDFA. Please no ha all he cos o he OLT is sha ed among all he use s, hus gi ing o he ope a o he eedom o use se e al expensi e echniques a he OLT side. A Pseudo-Random Bi Sequence (PRBS) wi h leng h o 2 31 -1 was used as downs eam signal. Once di e en ially p ecoded inside he downs eam Pulse Pa e n Gene a o (PPG1), i was mixed wi h a 5 GHz elec ical oscilla o (no synch onized wi h he PPG1 clock), and he esul ing signal was d i en o he MZM. A he elec ical side o he ONU ecei e , a e he 70/30 op ical couple and he APD, a delay-and-mul iply scheme was implemen ed using s anda d elec ical mixe s. This 70/30 op ical coupling a io was ound op imum in o de o equilib a e ups eam and downs eam powe budge s, since he RSOA gain was ound o be o 20 dB and he back- o-back sensi i i y o he p oposed SCM ecei e was o -28.2 dBm (using no op ical couple ). Fo he 1.25 Gbps ups eam signal, we used ano he 2 31 -1 PRBS om a second pulse pa e n gene a o (PPG2), d i ing an RSOA in he ONU. Based on hose ONU/OLT designs, h ee di e en PON scena ios we e es ed, ying o keep a minimum sys em ma gin o 3 dB: i s a pu e TDM ne wo k wi h low co e age (8 use s) used as a e e ence; secondly an s anda d medium hyb id TDM/WDM PON co e ing 160 use s; and inally an op imized ne wo k capable o se e 1280 use s. The i s scena io was assembled as a 25 km eede spool, ollowed by a 1:8 powe spli e and a 2.2 km d op spool; in a single- ibe con igu a ion. This is shown in Fig. 2. I was in ended as an access ne wo k o a la ge a1144_1.pd OSA / OFC/NFOEC 2010 NWB5.pd co e age a ea and low densi y o use s, capable o se e up o 8 use s. Thus, a pu e TDM con igu a ion was es ed and sa ed as a e e ence. El. Osc. MZM Tx LASER DATA Down APD DATA Up LPF APD τ 6 dB spli e DATA Down RSOA DATA Up BER1 PPG1 PPG2 LPF BER2 OLT ONU BPF PON PON 70:30 Couple -60 -55 -50 -45 -40 -35 -30 0 1000 2000 3000 4000 5000 6000 7000 F equency (MHz) Powe (dBm) (a) -65 -60 -55 -50 -45 -40 -35 0 1000 2000 3000 4000 5000 6000 7000 F equency (MHz) Powe (dBm) (b) -80 -70 -60 -50 -40 -30 -20 -10 0 1000 2000 3000 4000 5000 6000 7000 Powe (dBm) F equency (MHz) (d) -80 -70 -60 -50 -40 -30 -20 -10 0 1000 2000 3000 4000 5000 6000 7000 F equency (MHz) Powe (dBm) (c) Fig. 1. Le : ONU and OLT schema ic. Righ : Elec ical powe spec ums a he ecei e side: (a) be o e il e ing a he ONU, (b) a e il e ing a he ONU; (c) be o e il e ing a he OLT, and (d) a e il e ing a he OLT. 25 km 2.2 km ONU OLT 1:8 Powe spli e 16 km OLT 1:4 Powe spli e 1x40 AWG 2.4 km ONU 2.2 km Fig. 2. Schema ics o scena io 1 (le ) and scena io 2 ( igh ). In his i s case, o al ne wo k losses we e measu ed o be 16 dB. The ONU inpu powe was o -16 dBm, and i s ou pu powe was measu ed o be o +1 dBm, meaning ha he ONU ne gain was o 17 dB and he RSOA gain was o 20.5 dB. 0 dBm we e injec ed om he OLT o he eede ibe , gene a ing a measu ed Rayleigh Backsca e ing (RB) o -33.5 dBm (ha ing a 17.5 dB o ups eam op ical Signal o Rayleigh-backsca e ing Ra io, oSRR). Unde hese condi ions, ups eam and downs eam ansmission cu es we e measu ed. Resul s a e shown in Fig. 3. Fo he downs eam we ound a sensi i i y o -20.1 dBm, while o he ups eam he sensi i i y ound was o -18.4 dBm, bo h o a BER o 10 -10 . This means ha we achie ed a downs eam powe budge o 20.1 dB (sys em ma gin o 4.1 dB) and an ups eam powe budge o 19.4 dB (sys em ma gin o 3.4 dB). -12 -10 -8 -6 -4 -35 -30 -25 -20 -15 Inpu Powe a ONU (dBm) log(BER) Scena io 1 Scena io 2 Scena io 3 -12 -10 -8 -6 -4 -35 -30 -25 -20 -15 Inpu Powe a OLT (dBm) log(BER) Scena io 3 Scena io 2 Scena io 1 Fig. 3. Downs eam sensi i i y cu es o he h ee di e en scena ios (le ), Ups eam sensi i i y cu es o he h ee scena ios ( igh ) The second es -bed was composed o a 16 km eede spool, ollowed by a 1:40 AWG demul iplexe . Nex o i , a 2.4 km dis ibu ion spool was p eceding a 1:4 powe spli e and a 2.2 km d op spool. This is shown in Fig. 2 ( igh ). This scena io was o an a ea wi h medium densi y o use s, capable o se e up o 160 use s. To al ne wo k losses we e measu ed o be 16.4 dB. The ONU inpu powe was -16.4 dBm, and i s ou pu powe was measu ed o be o +0.8 dBm, meaning ha he RSOA gain was o 20.7 dB. Also, 0 dBm we e injec ed om he OLT o he eede ibe , gene a ing a RB o -33.5 dBm; and ha ing a 17.5 dB o ups eam oSRR, oo. Again, ups eam and downs eam ansmission cu es we e measu ed. Resul s a e shown in Fig. 3. Fo he downs eam we ound a sensi i i y o -20.6 dBm, while o he ups eam he sensi i i y ound was o -19 dBm, bo h o a BER o 10 -10 . This means ha we achie ed a downs eam powe budge o 20.6 dB (sys em ma gin o 4.2 dB) and an a1144_1.pd OSA / OFC/NFOEC 2010 NWB5.pd ups eam powe budge o 19.8 dB (sys em ma gin o 3.4 dB). Finally, an upg aded hi d es -bed was assembled. In his case, a double ibe eede is p oposed, so he RB amoun gene a ed was e y low; only due o de dis ibu ion and d op s ages. Now a couple o 16 km eede spools we e implemen ing a double ibe pa h om he OLT o he AWG. Nex o i , a 2.4 km dis ibu ion spool was p eceding he 1:32 powe spli e and a 2.2 km d op spool. This is shown in Fig. 6. Also, an op ical p eamp was used o ups eam de ec ion, since he e was no RB limi a ion, and OLT cos s a e sha ed among all use s. This scena io was in ended as an imp o ed access ne wo k, co e ing as many use s as possible (up o 1280). 16 km 16 km 2.4 km 2.2 km 1x40 AWG 1:32 Powe spli e ONU MZM PPG1 OLT Tx LASER To pho ode ec ion Fig. 6. Scheme o scena io 3 Now, o al ne wo k losses we e measu ed o be 26.6 dB. The ONU inpu powe was o -16.6 dBm, and i s ou pu powe was measu ed o be o +0.8 dBm, as in he second scena io. Please no e ha he Rayleigh backsca e ed signal was negligible, and he OLT ou pu powe could be inc eased o +10 dBm. Unde hese op imized condi ions, ups eam and downs eam ansmission cu es we e measu ed. Resul s a e shown in Fig. 3. Fo he downs eam we ound a sensi i i y o -19.6 dBm, while o he ups eam he sensi i i y ound was o -28.8 dBm, bo h o a BER o 10 -10 . This means ha we achie ed a symme ical powe budge o 29.6 dB (sys em ma gin o 4 dB). Table 1 shows a summa y compa ison be ween he h ee scena ios. Tab. 1. Summa y o he 3 scena ios Powe Budge Ups eam Downs eam Sys em ma gin Scena io 1 20.1 dB 19.4 dB 3.4 dB Scena io 2 19.8 dB 20.6 dB 3.4 dB Scena io 3 29.6 dB 29.6 dB 4 dB Conclusions An ad anced hyb id TDM/WDM access solu ion has been s udied and expe imen ally demons a ed. I is based on he ansmission o 2.5 Gbps SCM downs eam and 1.25 Gbps ups eam using colou less e lec i e ONU. Th ee scena ios we e e alua ed: La ge co e age a ea and low densi y o use s; a ea wi h medium densi y o use s; and imp o ed access ne wo k, co e ing as much use s as possible. In he i s and second es -beds, ansmission expe imen s ha e shown a ne wo k powe budge o 20 dB, o a single ibe con igu a ion, combined wi h he capaci y o se e up o 160 use s. Fo he hi d one, he powe budge could be inc eased up o 29 dB, ma ching clea ly he ypical alues o GPON deploymen s, and se ing up o 1280 use s. In all he cases a minimum sys em ma gin o 3 dB was achie ed. This wo k was suppo ed by Tellabs, he EU-FP7 SARDANA p ojec , and he MEC PTA-2003-02-00874 g an . Re e ences [1] W. Hung, C-K Chan, L-K Chen and C. Lin, "Sys em cha ac e iza ion o a obus emodula ion scheme wi h DPSK downs eam a ic in a WDM access ne wo k", in P oceedings ECOC 2003, Rimini, We3.4.5 (2003). [2] J. P a , C. A ellano, V. Polo, and C. Bock, ”Op ical Ne wo k Uni Based on a Bidi ec ional Re lec i e Semiconduc o Op ical Ampli ie o Fibe - o- he-Home Ne wo ks,” Pho onics Technology Le e s, 17, 250-252 (2005) [3] K. Y. Cho, A. Mu akami, Y. J. Lee, A. Aga a, Y. Takushima, and Y. C. Chung, ”Demons a ion o RSOA-Based WDM PON Ope a ing a Symme ic Ra e o 1.25 Gb/s wi h High Re lec ion Tole ance,” in P oceedings OFC 2008, San Diego, OTuH4 (2008). [4] J.M. Fab ega e al, “Demons a ion o a ull duplex PON ea u ing 2.5 Gbps Sub Ca ie Mul iplexing downs eam and 1.25 Gbps ups eam wi h colou less ONU and simple op ics,” in P oceedings ECOC 2008, B ussels, We1.F.6 (2008) a1144_1.pd OSA / OFC/NFOEC 2010 NWB5.pd