Non-linear effects in PON fibre channel

Transcription

1 Task 2 ad hoc on high slit EPON systems Non-linear effects in PON fibre channel Sergey Y. Ten (tens@corning.com) Corning Otical Fiber Silvia Pato (silvia.ato@siemens.com) Siemens Networks S.A. IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 1

2 Task -2- Particiants David Li, Ligent Photonics, Inc. Glen Kramer, Teknovus Inc. Marek Hajduczenia, Siemens Networks S.A. Ruben Luis, Siemens Networks S.A. Sergey Y. Ten, Corning Otical Fiber Silvia Pato, Siemens Networks S.A. Wael William Diab, Broadcom Cororation IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 2

3 Introduction higher slitting ratios (1x64 and 1x1) roblem: higher slitter losses higher launched ower to achieve the same erformance target: assess the system degradation caused by nonlinearities assess the maximum allowed launched ower with minimized non-linear effects Simulation analysis Analytical estimation Linear effects Nonlinear effects Attenuation Fiber disersion Self-Phase Modulation (SPM) Stimulated Brillouin Scattering (SBS) Stimulated Raman Scattering (SRC) IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 3

4 Simulation assumtions λ = 155 nm (downstream channel) external modulation in the OLT TX NRZ modulation format α =. db/km L OLT-PSC = 4 km ( km for PX1/ systems + extended reach for comarison) L PSC-ONU = 4 km ( km for PX1/ systems + extended reach for comarison) single PSC module with 64 / 1 orts (deending on scenario) fibre channel transmission effects attenuation disersion Self-Phase Modulation (SPM) IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 4

5 Simulation results (1 ONUs) Maximum launched ower [dbm] to guarantee a normalized eye oen enalty not exceeding 1 db 4 4 Length OLT - PSC [km] Length OLT - PSC [km] Length PSC - ONU [km] Length PSC - ONU [km] Nonlinear fibre between PSC and ONUs Linear fibre between PSC and ONUs IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 5

6 Simulation results (64 ONUs) Maximum launched ower [dbm] to guarantee a normalized eye oen enalty not exceeding 1 db 4 4 Length OLT - PSC [km] Length OLT - PSC [km] Length PSC - ONU [km] Length PSC - ONU [km] Nonlinear fibre between PSC and ONUs Linear fibre between PSC and ONUs IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 6

7 Simulation results - conclusions SPM does not limit the 1G 155nm no significant degradation in the systems erformance very high launched owers are admissible without enalties linear transmission in the dro sections (PSC <-> ONUs) signal ower level is already quite low nonlinear effects may be neglected dro section contribute to enalty through additional disersion IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 7

8 Exerimental Observation of SBS (Reminder) Inut (signal) ower otical fiber with given index rofile Transmitted ower Reflected ower backscattered light in forward direction 1 γ B Power ν B ν reflected ν B ~1 GHz ν signal Freq reflected ower, dbm Fiber 1 Fiber inut ower, dbm IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 8

9 SBS analytical estimations assumtions P CW SBS A g ao B k L SBS eff 1 L eff = ν SBS + ν P ν SBS ex( αl) α Stimulated Brillouin Scattering (SBS) calculations from first rinciles are difficult due to comlex nature of interaction of light wave with acoustic waves exressed by A ao but scaling with length and source linewidth is straightforward Assumtions: α =. db/km with comlete olarization scrambling (k SBS = 3/2) Brillouin bandwidth (Δν SBS ) = 5 MHz and light source CW linewidth (Δν P ) = 5 MHz Feeder length Effective length A ao 2 f ( r) rdr 2 = 2π ξ ( r) rdr 2 ξ( r) f ( r) rdr Worst case SBS (PSC near ONUs) km 12.6 km 2 Best case SBS (PSC near OLT).5 km.49 km IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 9

10 SBS threshold definition (ITU-T 65.2) Fiber A Reflected Fiber B Reflected Fiber C Reflected Fiber A Transmitted Fiber B Transmitted Fiber C Transmitted 1 Reflected Power [dbm] (8.1) (1.4) (11.4) Inut Power [dbm] Fiber A G.652 comliant fiber with Aeff=85 µm 2 Fiber B G.655 comliant fiber with Aeff=72 µm 2 Fiber C G.652 comliant fiber with Aeff=88 µm 2 (with enhanced SBS threshold) IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 1

11 SBS threshold for G.652 fibers results SBS (CW) Worst case Best case SBS (1 Gbit/s NRZ) Worst case Best case SRS Threshold ower 8.1 dbm.2 dbm 11.1 dbm.2 dbm slides worst case scenario long feeder section, PSC near ONUs best case scenario short feeder section, PSC near OLT SBS is the fundamental limitation SBS threshold enhanced G.652 fibers imrove SBS threshold by >3 db minimizing SBS related imairments with active equiment increase the source linewidth directly modulated source high disersion 155nm!! frequency dithering to the laser source directly modulating the laser with a sinusoid at a frequency significantly lower than the low-frequency cutoff of the receiver the dither frequency is outside the receiver bandwidth, so it will not degrade the signal in the resence of disersion u to a certain limit IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 11

12 Stimulated Raman Scattering (SRS) Reminder Raman um (co-) otical fiber Raman um (contra-) Raman Gain (1/km-W) Signal (P S ) α energy transfer (honon emission) Wavelength (nm) α s SRS tyically starts at higher ower than SBS For a single wavelength energy transfer from signal to Stocks comonent is unlikely because SBS will occur first and limit the signal ower. IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 G dp dz dp s dz R = Amlified Signal P S C R λ = λ = ex A P P s s g C R R eff,raman α P P s s α P s P () α P ( ) α z 1 e 12

13 Raman Interaction of two signal waves RF overlay is deloyed Low ower digital signal acts as Raman um for high ower analog signal Raman interaction causes two enalties Power deletion of digital signal CNR degradation of analog signal Pum deletion Digital signal at 149 nm CNR Degradation Analog signals at 155nm Raman Gain Sectrum IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 13

14 Digital Signal Deletion Signal Deletion Digital Signal Power Loss(dB) Analog Signal Power (dbm) Digital signal suffers from loss of ower as the analog signal ower is increased Effect occurs at current launched analog ower levels (~18 dbm) and gets worse at higher ower levels Overcome by launching higher ower digital signal IEEE82.3 Plenary Meeting, Dallas, TX, November 14-16, 6 14