1. Transparent Ring Interconnection Using Multi-wavelength Photonic switches WP 5 Transmultiplexers

2. Transparent Ring Interconnection Using Multi-wavelength Photonic switches2 Agenda Original Work-plan –Overall concept –Expected activities –Expected outcomes –Deviations from work-plan Design Phase –Routing node Network requirements Performance specification –WDM to OTDM conversion Alternative approaches Modelling of primary solution Preliminary experimental results –OTDM to WDM conversion Chirped pulse based converter WDM source based converter Broadband switch development Recent proposals Fabrication –Chirped pulse generator For OTDM to WDM For WDM to OTDM Summary

3. Transparent Ring Interconnection Using Multi-wavelength Photonic switches3 Work-Plan 160 Gbit/s Retiming Unit Optical Gate Multiplexer 4 x 40 Gbit/s 2R Regenerator / Wavelength converter 160 Gbit/s 160 GHz CRU Chirped of WDM Pulse Generation 4 x 40 Gbit/s ORC UCC WP4 WP3

4. Transparent Ring Interconnection Using Multi-wavelength Photonic switches4 Network Requirements WB SMF+DCF 2R G1G1 G2G2 G3G3 WB OTDM to WDM WDM to OTDM P down P in P out L MUX : -6dB -6dB L WB : -6dB LFLF L C : -3dB Independent transmitters –Free running phase (or even frequency) Collector and Core ring dimensions Loop back enabled Signal wavelengths –Fixed ITU based grid –Known wavelengths Simpler router design –Arbitrary wavelengths Routing flexibility Channel bit rates OSNR limit on WDM to OTDM converter WDM to OTDM converter should be regenerative WDM O2R is required to restore margin, and relax constraints on routing node

5. Transparent Ring Interconnection Using Multi-wavelength Photonic switches5 Channel Synchronisation Options Timing Drift of WDM Channels –Clock drift (4.6 ppm ≡ 5 ns coherence time) –Fibre expansion (0.5 ns/100km/ °C) –Wavelength drift with residual dispersion (0.6 ps/GHz) Continuous Traffic: Phase locked loop limited by VCO bandwidth or delay line range Burst Mode Traffic: Packet Compression –Burst length limited by chirp or loss in compressor Burst Mode Traffic: Asynchronous retiming –Burst length limited by clock precision Transmitter Node Local Clock Local Clock X Hold over mode Transmitter Phase comparison Local clock Error signal (with delay) Delay Line Error signal Local clock Packet Compressor

6. Transparent Ring Interconnection Using Multi-wavelength Photonic switches6 Specification tables Input Value Output value Packet Compressio n. Asynchronou s Retiming Distributed PLL Wander< 15ns p-p Bit wise <25 ps p-p Burst wise < 15 ns p-p < 25 ps p-p Random Jitter < 400 fs rms < 200 fs rms < 300 fs rms Deterministic Jitter < 1 ps p-p<500 fs p-p< 300 fs p-p Clock Offset< 200 kHz< 800 kHz< 0 kHz Packet Length < 4000 byte burst Continuou s Bit Rate (Gbit/s) 42.65691170.627656 Modulation Format 33% RZRZ Signal frequencies From 192.5, 193.1, 193.7, 194.3THz 191.9 THz or 192.5 THz, fixed OSNR> 40 dB> 30 dB Power Uncertainly < 6dB< 3dB Input ValueOutput Value Wander< 30 ns p-p< 30 ns guard band Random Jitter< 200 fs rms400 fs rms Deterministic Jitter< 1 ps p-p2 ps p-p Clock Offset< 200 kHz200 kHz Bit Rate (Gbit/s)170.6276442.65691 Modulation FormatInterleaved RZRZ or NRZ OSNR> 20 dB Power per channel> 0 dBm> -10 dBm Channel frequencies193.1 or 193.7 THz 193.1, 193.7, 194.3, 194.9 THz fixed WDM to OTDM OTDM to WDM

7. Transparent Ring Interconnection Using Multi-wavelength Photonic switches7 Phase margin in optical gates Synchronisation Unit Wavelength Converter Power Equaliser (O2R) Square Pulse Generation TRIUMPH grating design

8. Transparent Ring Interconnection Using Multi-wavelength Photonic switches8 Synchronisation unit 4x1 Switch Retimed Output Control circuit G1G1 G2G2 G3G3 G4G4 Degraded Square Pulse Input T/4 T/2 3T/4 T/4 T/2 3T/4 Local Clock Synchronisation Unit Wavelength Converter Power Equaliser (O2R) Square Pulse Generation

9. Transparent Ring Interconnection Using Multi-wavelength Photonic switches9 Synchronisation Unit Output Local Clock Control circuit Wavelength Selective Switch WDM Input Requires fixed, known input wavelengths 4 Active optical switches

10. Transparent Ring Interconnection Using Multi-wavelength Photonic switches10 Single EAM ADORE OC: optical circulator BF: birefringent fiber FR: Faraday rotator PBS: polarization beam splitter 6.25ps offset 12.5ps by BF 45 o OC 3-dB coupler PIN EAM Control circuit Resynchronized output PBS FR Input signal Local optical clock pulse 2ps FWHM Optical switch

11. Transparent Ring Interconnection Using Multi-wavelength Photonic switches11 Single EAM ADORE OC: optical circulator BF: birefringent fiber FR: Faraday rotator PBS: polarization beam splitter 6.25ps offset 12.5ps by BF 45 o OC 3-dB coupler PIN EAM Control circuit Resynchronized output PBS FR Input signal Optical switch Clock phase Ch1+Ch2 Clock phase Ch3+Ch4 Local optical clock pulse 2ps FWHM

12. Transparent Ring Interconnection Using Multi-wavelength Photonic switches12 WDM-to-OTDM Conversion 4 ADOREs, sharing the same high quality local laser clock source and with appropriate delays following them to time interleave the regenerated signals Only 4 Active optical switches required 160Gb/s OTDM signal 4x40Gb/s WDM signals Local optical clock Blue line: electrical domain ADORE PD 25ps

13. Transparent Ring Interconnection Using Multi-wavelength Photonic switches13 Preliminary Experiment PIN EAM Input signal 40Gbit/s RZ CW

14. Transparent Ring Interconnection Using Multi-wavelength Photonic switches14 TDM-to-WDM conversion Implementation of this conversion is challenging First attempt at lower repetition rate: conversion provided by a rectangular shaped, linearly-chirped pulse Optical Switch OTDM data WDM data signal WDM data signal Broadband signal Broadband signal

15. Transparent Ring Interconnection Using Multi-wavelength Photonic switches15 NOLM switching with linearly chirped pulses  0 =2.5ps  0 ~   0 =9.5ps  0 ~ 

16. Transparent Ring Interconnection Using Multi-wavelength Photonic switches16 Bandwidth requirement and channel separation Total bandwidth required for producing switched pulses is related to the specified chirp-width product (C  0 2 ). Minimum bandwidth requirement for the linearly chirped pulse at C  0 2 = 0.6 as a function of the aggregate OTDM bit rate and WDM channel separation as a function of the line bit rate

17. Transparent Ring Interconnection Using Multi-wavelength Photonic switches17 OTDM-to-WDM conversion Alternative technique: 4 synchronized WDM channels Pulse carving at 40 GHz using EAMs. WDM data Signal Broadband Signal DFB1 DFB2 DFB3 DFB4 EAM1 EAM2 EAM3 EAM4 1 2 3 4 OTDM data Signal Or Kerr switch

18. Transparent Ring Interconnection Using Multi-wavelength Photonic switches18 Switched pulses in time and wavelength P control =16dBm D@1550=0ps/nm/km <10dB D@1550=-0.8ps/nm/km P control =16dBm ~ 30dB 7% 30%

19. Transparent Ring Interconnection Using Multi-wavelength Photonic switches19 Switched pulse - different settings 24% ~25dB P control =16dBm D@1550=0ps/nm/km D@1550=-0.8ps/nm/km P control =20dBm <10dB 7%

20. Transparent Ring Interconnection Using Multi-wavelength Photonic switches20 Subsystems for optical router WDM to OTDM –ADORE appears feasible and cost effective Wavelength conversion –Not required –2R regeneration would be of benefit Clock recovery –See WP3 WDM to OTDM –Difficulties experienced which require understanding of pulse quality / cross talk trade offs –Refined design using NPR imminent