Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Lightwave Communications Lab. Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Lightwave Communications Laboratory Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Mission R and D of advanced lightwave systems technologies and applications in high-capacity optical communication systems and broadband networks. Team C. K. Chan, L. K. Chen, Frank Tong, K. W. Cheung, Chinlon Lin & graduate students (13 in 2003/04) Architectures of high-speed optical metro/access networks and system technologies Photonic signal processing technologies for lightwave systems Performance surveillance of optical systems and networks Optical networking techniques Research thrusts Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Research Thrusts Architectures of high-speed optical metro/access networks and system technologies -bidirectional transmission, DWDM & CWDM, OADM, OXC, protection architectures, novel modulation schemes, broadband applications, etc. Photonic signal processing technologies for lightwave systems - optical waveform restoration, wavelength conversion, channel demultiplexing and switching, signal regeneration, OTDM, etc. Performance surveillance of optical systems/networks - fault detection, optical path supervision, signal-to-noise ratio monitoring Optical networking techniques - protection switching, restoration, multi-access protocols, routing, label- switching, and performance analysis Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Optical access networks Access network protection and restoration in WDM-PON T.J. Chan, et al., A Self-Protected Architecture for Wavelength Division Multiplexed Passive Optical Networks, IEEE PTL, Nov C.M. Lee, et al., A Group Protection Architecture (GPA) for Traffic Restoration in Multi-wavelength Passive Optical Networks, ECOC03, Paper Th WDM-PON upstream transmission using carrier re-modulation N. Deng, et al., Experimental Investigation of Re-modulating Upstream OOK Data on Downstream OFSK Signal in a Two-Way WDM Access Network, IEEE CLEO/Pacific Rim W. Hung, et al., An Optical Network Unit for WDM Access Networks with Downstream DPSK and Upstream Re-modulated OOK Data Using Injection- Locked FP Laser, IEEE PTL, Oct L.Y. Chan, et al., Upstream Traffic Transmitter Using Injection-Locked Fabry- Perot Laser Diode as Modulator for WDM Access Networks, EL, 38, 1, Jan S. Y. Cheung, et al.,Demonstration of an ONU for WDM Access Network with Downstream BPSK and Upstream Remodulated OOK Data Using Injection- Locked FP Laser, ECOC '01, Paper We.B.3.2. Upstream multi-access protocol for TDM-PON Y.T. Tse, et al., A Distributed Collision Avoidance Protocol using Pilot Tone- based Carrier Sense Mechanism for Passive Optical Networks, OFC'03, Paper TuR4. Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong OLT: Optical Line Terminal ONT: Optical Network Terminal ONU: Optical Network Unit NT: Network Terminals Network architecture design Bi-directional transmission Performance surveillance Wavelength channel routing Protection and restoration Broadband Services: Data, Voice, Video and VoIP, IP Video, etc.. 1, , N 1 N i j Residential Buildings and Houses Wavelength Mux/Demux RN: Remote Node Multi-wavelength passive optical access networks Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Protection and traffic restoration in WDM-PONs Multi-wavelength optical access network architecture 1:1 protection against fiber cut and automatic traffic restoration via fast wavelength re-routing Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Data re-modulation for upstream transmission in multi-wavelength optical access networks Upstream OOK Transmitter Downstream Modulation Format (Demonstrated) OOKRF BPSKDPSKOFSK Injection- Locked FP laser 1-Gb/s1.25- Gb/s2.5- Gb/sN/A External Modulator N/A 2.5- Gb/s2.5- / 10-Gb/s Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Signal processing and conditioning Waveform restoration techniques to mitigate SOA induced pattern effect K. Chan, et al., Polarization Insensitive Waveform Restoration and Channel Crosstalk Reduction in Semiconductor Optical Amplifier Gate Using Polarimetric Filtering, IEEE PTL, Nov K. Chan, et al., Waveform Restoration in Semiconductor Optical Amplifier Using Fiber Loop Mirror, IEEE PTL, Jul Low-penalty OTDM channel demodulation with SOA-based demultiplexer using RZ-DPSK K. Chan, et al., Mitigation of Pattern-Induced Degradations in SOA-Based All-Optical OTDM Demultiplexers by using RZ-DPSK Modulation Format, IEEE PTL, Sep Optical-sampled subcarrier multiplexing scheme for nonlinear distortion reduction W. Hung, et al., An Optical Sampled Subcarrier Multiplexing Scheme for Nonlinear Distortion Reduction in Lightwave CATV Networks, IEEE GLOBECOM '02, Paper OPNT Homodyne Crosstalk Suppression Using Optical Regeneration All-Optical Exclusive LOGIC (XOR) Study of Polarization Mode Dispersion (PMD) Optimization of Supercontinuum Generation Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong 40-Gb/s to 10-Gb/s all-optical time-division demultiplexing with RZ-DPSK modulation format Negligible patterning induced penalty Enhanced input signal power dynamic range Semiconductor Optical Amplifier average received power (dBm) log (BER) Baseline received power (dBm) log (BER) GHz Control Pulse DPSK Demodulator (Delayed-Interferometer) ED OTDM Demultiplexer Polarization Controller Optical bandpass filter 40 Gbit/s RZ-DPSK 40 Gbit/s RZ-OOK OOKDPSK Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong To obtain stable and broadband spectrum-sliced optical sources for wavelength division multiplexing (WDM) optical transmission systems. Nonlinear fiber Optical pulse source High power optical amplifier Optical filter Optical filter The SCG along the fiber is governed by the following equation. Frequency (THz) Q (dB) High-order nonlinearities are included in such analysis. Fundamental limits on the system performance of SC sources are determined. SPM, dispersion and FWM all contribute to the system performance degradation. High-order nonliearities induce asymmetry on the Q (dB) profile. Performance optimization in supercontinuum sources Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong High-speed SOA-based all-optical exclusive-OR (XOR) gate with RZ-DPSK modulated inputs Easy all-optical XOR gate implementation Patterning-free operation Capable of ultra-high speed operation Delayed Interferometer PM Optical filter SOA PM I 100 ps/div Four-wave Mixing in SOA Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Optical packet network sub-systems Parallel Packet Header/label Recognition K. Chan, et al. An All-Optical Packet Header Recognition Scheme for Self- Routing Packet Networks, OFC '02, Paper WO4. Optical packet TTL countdown for Routing Loop Prevention W. Hung, et al., A Routing Loop Control Scheme in Optical Layer for Optical Packet Networks, OFC '02, Paper ThGG111. Optical packet labeling and label swapping using DPSK-encoded labels W. Hung, et al., A Bit-Serial Optical Packet Label Swapping Scheme using DPSK Encoded Labels, IEEE PTL, Nov W. Hung, et al.; A Novel Phase Encoding Scheme for Optical Packet Label Processing, ECOC03, Paper Tu4.4.4, Intensity-modulated labeling and all-optical label swapping on angle- modulated (ODPSK / OFSK) optical packets OLS network without label update Y. Zhang, et al., A Multi-Domain Two-Layer Labeling Scheme for Optical Packet Switched Networks with Label-Swapping-Free Forwarding, ECOC03, Paper Mo3.4.5, 2003. Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Phase labeling of intensity modulated optical packets Optical Label Switching enables fast packet forwarding in optical domain Labeling of packets needed to carry forwarding info. Packet: OOK; Label: DPSK Previous schemes: Extinction ratio of OOK packet sacrificed Bit serial DPSK labeling with simultaneous wavelength conversion and 2R regeneration Label Swapping Unit Packet Label 1 OOKDPSK PacketLabel 2 OOKDPSK Label 2 Interleaved DPSK labeling with low-data-rate Labels No need for packet ER reductionNo need for packet ER reduction Easy label swappingEasy label swapping 2R regeneration using SOA2R regeneration using SOA Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Intensity-modulated labeling on angle-modulated payload in optical packet networks OOK label on optical FSK or DPSK payload Largely simplify all- optical label swapping Label erasing is realized by nonlinear birefringence evolution in SOA 50 ps/div Packet waveform Payload eye-diagram ~ 1 dB power penalty after 40-km transmission with proper dispersion compensation < 0.2 power penalty induced for both label and payload signals after label swapping (i) after 40 km (at B) (ii) after LEU (iii) after label swapping (at C ). all 2 ns/div Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Optical Packet Time-to-live (TTL) Countdown Motivations Optical Label swapping brings about routing loop problem. Routing looping must be mitigated rapidly to prevent severe network congestion TTL countdown using SOA-based polarimetric switch TTL countdown based on periodic phase modulation The principle of optical packet TTL countdown Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Optical Network Management Performance Monitoring L.K. Chen, et al. Performance Monitoring in Transparent Reconfigurable WDM Networks, OECC03, (Invited Paper), Paper 14D M.H. Cheung, L.K. Chen, C.K. Chan, On Robustness of In-band Polarization-Assisted OSNR Monitoring Schemes Against PMD, IEEE CLEO/Pacific Rim 2003, 2003 Kit Chan, et al., Performance Supervision For Multiple Optical Amplifiers in WDM Transmission System Using Spectral Analysis, IEEE PTL, May Kit Chan, et al., A Novel FFT-based EDFA Supervisory Scheme for WDM Transmission Systems; ECOC '01, Paper We.P47. Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong FFT-based EDFA supervisory scheme AWG FBG Data channels Monitor BPF OBPF Loop length = L k s OA-1OA-2 OA-3 OA-M Frequency From OA-1 Fast Fourier Transform (FFT) From OA-2 From OA-3 S at Monitor EMEM E2E2 E3E3 E1E1 Identifiers for in-line EDFAs (1 to M) Frequency Receiving end Ref: Chan Kit et al, Performance Supervision for Multiple Optical Amplifiers in WDM Transmission System Using Spectral Analysis, IEEE PTL, Vol. 14, No.5, May 2002 Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Passive surveillance schemes using FBG EDFA Monitoring information Isolator WDM Receiver FBG Data channels Ref: Chan Chun-Kit et al, A Practical Passive Surveillance Scheme for Optically Amplified Passive Branched Optical Networks, IEEE PTL, Vol. 9, No.4, April EDFA Monitoring information Isolator WDM Receiver FBG Data channels 1 2 EDFA Isolator FBG Data channels 1 2 N Monitor BPF = Pump LD Ref: Chan Chun-Kit et al, A novel in-service surveillance scheme for optically- amplified transmission system, IEEE PTL, Vol. 9, No.11, Nov 1997 Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Recent Publication in Major Conferences and Journals OFC324 ECOC26 PTL225 JLT1 EL2 Website: Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Some statistics Ph.D. and M.Phil. student number Ph.D. and M.Phil. student number Projects awarded Projects awarded Earmarked grant: 2 (2003); 13 (accumulated) Earmarked grant: 2 (2003); 13 (accumulated) ITF: 2 ITF: 2 Technology transfer: 1 Technology transfer: 1 Present Degree Awarded (as of Oct. 2003) Ph.D.42 M.Phil.919 Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Thank You! Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Homodyne crosstalk tolerance enhancement by MZI-SOA wavelength converter 7.9 dB homodyne crosstalk tolerance enhancement BERT Receiver External Modulator EDFA 50:50 6-km SMF PC Optical Attenuator DFB Laser nm SOA BPF nm DFB Laser nm All-active MZI-SOA Data Signal Crosstalk 2.5-/ 10-Gbps NRZ PRBS PC BPF nm Signal distorted by homodyne crosstalk Regenerated signal Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong Investigation of SPM effect on frequency-resolved SOP rotation and its application to PMD monitoring PMD SPM Broadened signal spectrum relaxes filter requirement and computation complexity. Lightwave Communications Lab Centre for Advanced Research in Photonics The Chinese University of Hong Kong PMD-insensitive optical signal-to-noise ratio (OSNR) monitoring using polarization-nulling with off- center narrowband filtering Enhanced robustness to polarization-mode- dispersion (PMD) Simple configuration Power meter Narrowband optical bandpass filter Power meter Optical bandpass filter /4 Plate Polarizer Incoming monitoring signal Total power Half ASE noise power OSNR monitor 10-Gb/s RZ system DGD (ps) Monitoring Error (dB) w/o narrowband filtering w narrowband filtering 40-Gb/s OTDM system DGD (ps) Monitoring Error (dB) w/o narrowband filtering w narrowband filtering