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Fotonica in SURFnet6 Wouter Huisman Netwerkdiensten, SURFnet

Fotonica in SURFnet6 Wouter Huisman Netwerkdiensten, SURFnet. Agenda. Fibers & Infra Module Blocks Transmitter, Receivers, Amplifiers, Filters Systems Single channel lasers/receivers Amplified single channel C/DWDM DCM, PMD, FEC Latest technology SURFnet’s network.

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Fotonica in SURFnet6 Wouter Huisman Netwerkdiensten, SURFnet

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  1. Fotonica in SURFnet6Wouter HuismanNetwerkdiensten, SURFnet

  2. Agenda • Fibers & Infra • Module Blocks • Transmitter, Receivers, Amplifiers, Filters • Systems • Single channel lasers/receivers • Amplified single channel • C/DWDM • DCM, PMD, FEC • Latest technology • SURFnet’s network

  3. Internal reflection known from 19th century (John Tyndall, 1870) Early fibers with cladding extremely lossy ~1000dB/km (1960) Today fiber loss ~0.2dB/km Optical fiber - Historical perspective Refractive index N1(water) > N2 (air)

  4. Fiber basics • Multi Mode (MM) • Intra office • SX • max 500m • Single Mode (SM) • LX, ZX, C/DWDM 50 - 62µm Core Cladding 5-10µm

  5. Fiber Loss (SM) • Fiber loss is wavelength dependent, minimum is around 1550nm 1310nm 1470nm-1620nm

  6. Fiber plant layout POP Equipment MMR ~4km ~4km Splice Handhole Patching at ODF

  7. Fiber Plant test • Basic paramaters: • - Length • - Loss • - Reflection OTDR (optical time domain reflectometer)

  8. 10Gb/s optical transmitter technologies • External Modulation - DM-DFB (Directly Modulated Distributed Feed Back laser) • Cheap, small, low power consumption • Chirped, i.e. different wavelength during “ones” and “zeros” which leads to a wide optical spectrum and associated transmission impairments • Used for short reach transmission {0,1,1,0,1,1,…,0,1,0} DFB • External Modulation - CW-DFB (Continuous Wave DFB laser) and MZ (Mach-Zehnder) combination • Expensive, relatively large, high-power drivers (high power consumption) • Excellent performance • Typically used for DWDM (Dense Wavelength Division Multiplexing) {0,1,1,0,1,1,…,0,1,0} DFB Mach-Zehnder LiNbO3 modulator

  9. decision circuit preamp AGC (A)PD CLK Typical optical receiver setup data BER 10-6 10-9 10-12 Prec (dBm) Psens

  10. Traditional optical fiber transmission systems • Combination of transmitter and receiver connected directly to dark fiber • Typical distance is max 100km • 150Mb/s -2.5Gb/s Transmission fiber α (dB/km) Tx Rx PT (dBm) PR (dBm) Transmission distance = (PT-PR) / α (km)

  11. Tx Tx Tx Rx Rx Rx 3R regeneration - OEO Transmitter – Receiver = 3R • Re-amplification • Re-timing • Re-shaping

  12. EDFAs (Erbium Doped Fiber Amplifiers) • Fiber doped with Er3+ ions be excited by 980nm or 1480nm photons • Spontaneous emission generates noise • Excited state Erbium ions can be stimulated to decay to ground state via stimulated emission by a 1550nm signal Pump laser Outgoing Incoming

  13. Single Channel System with amplifiers Tx Rx OA OA • Pre and Post Amplifiers allow for longer single span Systems upto 240km • 150Mb/s -2.5Gb/s OLA Tx OLA Rx OA OA

  14. Wavelength Division Multiplexing (C/DWDM) • WDM filters, passive device • Muxing coloured wavelength • Spacing between ’s determines the number of channel per fiber • SURFnet’s DWDM supports 72 ’s @ 10Gb/s

  15. DWDM System Terminal Node AMP Node OADM Node Terminal Node OEO OEO DCF … DCF DCF Mux … Demux DCF DCF OEO OEO OEO OEO … Mux … Demux DCF DCF DCF DCF DCF OEO OEO OEO • Typically 80 channels spaced at 100GHz using C and L band • Each channel operating at 10Gb/s, thus 800Gb/s per fiber • Limited Optical Add and Drop for point-to-point optical lightpaths

  16. Chromatic Dispersion • Typical value dispersion (D) 17ps/nm*km 10Gb/s F T ~ bitperiod L = Tb/ F*D

  17. ƒ 1 1 2 2 Chromatic Dispersion 120km standard SMF D=17.8 ps/nm km Tx Rx OA OA rb = 10Gb/s c = 1557nm 120km-10Gb/s system configuration 011101101001001 011101101001001 Optical pulse shape at transmitter output After 120km transmission Speed of Light is Wavelength dependent: Chromatic dispersion affects pulse shape

  18. PMD

  19. Psens FEC • Forward Error Correction • Technique to improve bit error rate resulting better Preceiver • Adding FEC increases bitrate  worse Preceiver FEC on BER 10-6 10-9 10-12 Prec (dBm) Parity check indicates the single error bit

  20. New developments • 40Gb/s and 100Gb/s • QPSK/QAM 40G over 10Gb/s From Static to Dynamic: • MEMS – Switchable mirrors • Dynamic WDM • eDCM • Tunable lasers • Tunable filters • DRAC

  21. ROADM Node Terminal Node AMP Node Terminal Node OEO OEO OEO … … Mux Demux OEO OEO Layer 0 Evolution Terminal Node AMP Node OADM Node Terminal Node OEO OEO DCF … DCF DCF Mux … Demux DCF DCF OEO OEO OEO OEO … Raman Raman Raman Mux … Demux DCF DCF DCF DCF DCF OEO OEO OEO Advanced FEC Advanced Signal Processing Higher Spectral Efficiency (QPSK/QAM) Remove Raman, Increase Performance Remove DCMs & Amps, Increase PMD Tolerance, Eliminate complex engineering rules (esp. OADM) 4x Capacity per Line and 40G Service Support

  22. TWc SMF-28 TWc E-LEAF SMF-28 E-LEAF SMF-28 E-LEAF Dynamic Networking ROADM ROADM ROADM ROADM ROADM ROADM

  23. SURFnet6 • third generation DWDM • 10Gb/s per channel • 50GHz channel spacing • wavelength locking • optical add/drop • forward error correction • dispersion compensation • C-band, can be upgraded to add L-band

  24. Thanks!wouter.huisman@surfnet.nl

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