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DTU Fotonik , Department of Photonics Engineering, Technical University of Denmark, Building 343, 2800 Lyngby, Denmark

Evarist Palushani. DTU Fotonik , Department of Photonics Engineering, Technical University of Denmark, Building 343, 2800 Lyngby, Denmark epalu@fotonik.dtu.dk. Ph.D. in the NOSFERATU project. Outline. Project objectives Pulse shaping: Flat-top pulse generation:

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DTU Fotonik , Department of Photonics Engineering, Technical University of Denmark, Building 343, 2800 Lyngby, Denmark

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  1. Evarist Palushani DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, Building 343, 2800 Lyngby, Denmark epalu@fotonik.dtu.dk Ph.D. in the NOSFERATU project

  2. Outline • Project objectives • Pulse shaping: Flat-top pulse generation: • Long Period Grating pulse shaper • Optical Fourier Transform technique • All-optical Retiming and Synchronization • Time Lens based Packet Synchronization

  3. Project objectives NOSFERATU:Non-linear optical switching for extremely high data rate communications

  4. Project objectives 2 • Optical Ethernet upgrade from futures 100 GE lines to 1 TE (Terabit Ethernet) • Definition of a network scenario • Development of techniques for network intelligence and efficient switching/routing • Investigation of optical effects and limitations for 1 TE Optical Time Division Multiplexing (OTDM) • Functionalities to be addressed, developed and investigated: • OTDM networking issues for optical 1 TE solutions • Stable 1 TE multiplexer • Pulse shaping for suitable terabit OTDM communications • Suitable nonlinear switches, for stable channel selection Ph.D. Ph.D. Post Doc.

  5. Outline • Project objectives • Pulse shaping: Flat-top pulse generation • Long Period Grating pulse shaper • Optical Fourier Transform technique • All-optical Retiming and Synchronization • Time Lens based Packet Synchronization

  6. Pulse Shaping for Demux Optimisation • Flat-top pulses suggested for: • Polarisation-independent (PI)1 NOLM operation when: • Correct adjustment of control pulse power (Pctrl) • Correct adjustment of control polarisation • Time jitter tolerance in OTDM switches2 1H. Mulvad, “Polarization-Independent High-Speed Switching in a Standard Nonlinear Optical Loop Mirror”, OFC 2008, Paper OMN3 2L.K. Oxenløwe,``640 Gb/s Timing Jitter-Tolerant Data Processing Using a Long-Period Fiber-Grating-Based Flat-Top Pulse Shaper,‘’ IEEE J. Quantum Electronics, vol.14, pp. 566-572 (2008)

  7. LPG1 LPG2 Input pulse L T Long Period Grating : Pulse Shaper L: spacing between filters T: time delay between coupled modes T= 400 fs Gaussian input pulse FWHM = 700 fs Wavelength tuning determines pulse shape

  8. 640 Gbit/s PI demultiplexing in a NOLM Polarisation scrambler on the data

  9. Outline • Project objectives • Pulse shaping: Flat-top pulse generation • Long Period Grating pulse shaper • Optical Fourier Transform technique • All-optical Retiming and Synchronization • Time Lens based Packet Synchronization

  10. C j-mod Dacc Optical Fourier Transform Technique (OFT): Pulse Shaper A0 A1 C : time lens linear chirp L : fiber length β2: dispersion temporal F1 F0 spectral for where Required combination of phase modulator and dispersive element Mapping of the spectrum shape into the time domain Possible to taylor the length of the output pulse by changing C

  11. OFT without Phase Modulation a0 a1 f0 f1 for Far field image yields optical waveform as the OFT of input Need wide input spectrum/narrow pulse, since no phase modulation Here: SPM spectral broadening and shaping by broad band-pass optical fiter

  12. simulated xcorrelator measured power [a.u.] + autocorrelator 16 SMF 8 m SMF for chirp compensation power [a.u.] time [ps] Result 1: Frequency-Time Information Mapping power [a.u.] FWHM=15 nm power [dBm] Good agreement between predicted and measured pulse shapes wavelength [nm]

  13. Result 2: Narrow flat-top gating pulse generation Pre-transform at L = 10 m SMF of very flat m~2 spectrum Mix between m=2 (pulse top) and m=1 (tails) Flat-top pulse shape with FWHM 1.6 ps ~ 640 Gbit/s timeslot

  14. 320 Gbit/s Demultiplexing: Timing tolerance • The flat-top pulse (gating signal) is used in a FWM demultiplexing experiment • 320 Gbit/s data signal used as pump • Flat top pulses (previous slide) used as probe Pre-transform flat-top pulse able to FWM-demux 160-320 Gbit/s Simultaneous switching window and timing tolerance measured 400 fs timing tolerance ~ switching window flat top 14

  15. Outline • Project objectives • Pulse shaping: Flat-top pulse generation: • Long Period Grating pulse shaper • Optical Fourier Transform technique • All-optical Retiming and Synchronization • Time Lens based Packet Synchronization

  16. All-optical Retiming and Synchronization From asynchronous 10 GE NRZ to synchronous 1 TE RZ

  17. Time Lens based Packet Synchronization Δf=fin-fL Nominal speed: fin Local clock: fL

  18. Results: Time Lens based Packet Synchronization Δf= 200 kHz Usynch. packets Synch. 5120 bits/packet Synch. 12144 bits/packet

  19. Thank you for your attention !

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