Photonics in Converged Packet Networks Presented Workshop on Future Optical Networks
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Photonics in Converged Packet Networks Presented Workshop on Future Optical Networks OFC 2007 Anaheim, CA March 25, 2007 Rod C. Alferness Research Senior Vice President Bell Laboratories Optical Transport Networking Evolution – A View from the ’90s WDM/Point-to-Point Transport – High Capacity Transmission Fixed WDM/Multipoint Network – Fixed Sharing Between Multiple Nodes – Passive Access of Wavelength Channels Photonic XC and WADM Reconfigured WDM/Multipoint Network – Automated Connection Provisioning – Flexible Adjustment of Bandwidth – Network Self-Healing/Restoration Significant Curent and Planned Deployment! Fiber Amplifier Wavelength Add/Drop Wavelength Multiplexer/ Demultiplexer Wavelength Cross-Connect What’s Next for Photonic Switching in the Network? First, some learnings • • Why WDM Networks Prevailed? Reduced Network and Operations Cost! Key Optical Switch Characteristic? Flow switch, Bit rate agnostic, slow (ms) acceptable Reasonable next steps for photonic switching? • • • Address New Converged Transport Architectures Architectures to Provide a Softer WDM to TDM or Packet Boundary Explore the role of photonics to scale packet switches and routers Explore and drive optical technologies that cost-effectively enable these directions Communications Network Architecture Mobility Network Management M Core Router IP/MPLS Service T Edge IP/ATM Service Edge WDM Core IP/MPLS Core T Edge Router L2 Access ATM/FR Edge Router EoMPLS Metro Core Ethernet/SONE /SDH Metro Core SONE/SDH Metro Access NG SONET CPE Mux Metro Aggregation EoMPLS Metro Access SDH MSPP (e.g., Metropolis® ADM-U Or NG-MUX) Ethernet Access Host Terminal (e.g., EFM Host) 802.16 BS Broadband Access V-16™ CPE FTTC ONU Stinger CPE NG SDH CPE Mux Mobility Next Gen Ethernet: 100GbE Why 100G Ethernet ? – – – Follow the historical trend … Access rates of 10G now, aggregation into higher rates required More capacity per wavelength needed in the future core Growing demand for data traffic (IP TV/Video, etc.) Enabling higher port/switching capacities per footprint 100 Speed [Gb/s] – – 100G 10 1 0.1 0.01 1980 1985 1990 1995 2000 2005 2010 Year First Demonstration of True 100G Transmitter by Bell Labs (ECOC 2005) Eye Diagram 107-Gb/s NRZ Aggregation of 10GE Server Farms Wavelength switching • Arrayed waveguide grating (AWG) – – – 2D integrated diffraction grating Commonly used as optical Mux/Demux Cheap piece of glass NxN periodic AWG FTTx Rx FTTx Rx FTTx Rx FTTx Rx Strictly non-blocking cross-connect with N connections. 1x N Example- WDM PON with Single Rapidly Tunable Laser Source Dedicated wavelength & fiber(s) to each home or business Internet Residences or Businesses ONU Single or dual fiber Router Phone ONU Gateway WDM OLT WDM Mux/ Demux Demarc Other Networks TV Video PC PSTN Switch Passive: no electronics, no power PSTN ONU Central Office Efficiency Time-Multiplexed WDM: Ring Architecture with WDM Scalability and TDM Granularity Deaggregator Aggregator Deaggregator Burst Tunable receiver laser Aggregator Burst Tunable receiver laser •Simple optical Add/Drop. •Sub-wavelength granularity. •Growable to full WDM. 10G/40G Data Envelopes Single Lambda drop Single Lambda drop N-Node Ring comparison: T-WDM Ring: Rx Bandwidth Granularity # of Transmitters /Receivers Bandwidth Efficiency Scalability SONET Ring 50 Mb/s N 1/N 10/40 Gb/s T-WDM Ring 50 Mb/s N Close to 100% 5 Tb/s WDM Ring 10 or 40 Gb/s N(N-1) 100% 5 Tb/s Tx Static OADM Tx Rx Rx Static OADM Tx Static OADM Static OADM Rx Tx Zirngibl, et al, Bell Labs, Alcatel-Lucent TWIN- Mesh Networks 2 5 4 1 7 3 6 2 5 1 4 2 1 5 4 7 7 3 Ethernet Packet Pre-configured WSSs with spanning tree routes for each destination 3 6 “End Node” Function 6 • Each destination node is assigned unique wavelength(s) address • Intermediate nodes are configured to form destination-based trees • Each source node uses a tunable laser to tag optical bursts ÎScheduled bursts passively & optically bypass intermediate nodes • reduces packet processing in the network “Intermediate Node” Function input ports passive combiner output ports Tx Packet assembler Tunable transmitter Fiber 1 2 1 2 K K Wavelength-Selective Switch (WSS) Saniee, et al, Bell Labs, Alcatel-Lucent Operation of TWIN — Example Collision is prevented using scheduling Clients Clients Tx Burst assembler • • Rx Burst disassembler Fast switching in the network core is emulated by fast tuning of wavelengths at the network edge and passive routing within network Flexible bandwidth for each client results from shift of transmitting wavelengths at source Photonics for the Data Packet Layer- Options and Evolution • Optical Interconnect • High-Speed Optical Switch Inside a Packet Router • In-Line Optical Packet Router – All-Optical Data Path (Elect. Control) – All-Optical Data and Control Fast Tunable Laser Module 2” Low-speed RS232 bus High-speed parallel bus 3” Lookup Table DAC Amp DAC Amp DAC Amp Laser Gain and Temperature Control and Monitor Microprocessor Wavelocker ADC SG -DBR Laser Gain Source Wavelocker • • ADC Diff Amp TIA Diff Amp TIA TEC Control Tunes between 64 ITU channels in less than 45 ns Wavelocker feedback improves frequency accuracy and prevents long-term drift Result: 64 port x 40 Gb/s per port Optical Switch Fabric Without Locker With Locker IRIS Optical Packet Router • DARPA MTO Data in Optical Domain Networking – – – • Highly integrated photonic chips Line Cards – – • Program to develop Technologies for High Capacity Optical Packet Router Scalable to >100Tb/s Multi-year program, Program Manger Dr J. Shah Partner with UC Santa Cruz (Prof Varma) and Lehigh University (Prof Koch) Highly integrated optical components • Denser integration of optical interfaces on line card • Data never converted to electronics for lower power Shallow Buffers • Demonstration of high throughput in routers with buffers 20 packet deep make using optical buffers possible Scalable Switch Fabrics – – Highly scalable non-blocking switch fabrics • 5Tb/s using AWG plus tunable lasers and 100Gb/s Transmitter Use of load balancing to allow blocking switch fabrics to be used • Scalability to 256 Tb/s throughput • Transparent optical packet router demonstrated Effects of shallow buffers 100Gb/s Packet switching Optical Packet Router InP Monolithic Integration • InP-based material structure (quaternary InGaAsP or InGaAlAs) – Low propagation losses (<0.5dB/cm) in passive ridge guides – 600µm bend radius at index step ∆ ~ 0.8% Active PLCs consist mainly of SOA as amplifiers, detectors, modulators, etc. Active Channel Waveguide p:InP Q W – MQW or bulk with active overlay or butt-joint – Low reflections at passive-active interface i:M • • i:InP SiO2 i:InP n:InGaAsP n:InP Passive Rib Waveguide Integrated Wavelength Conversion ModuleKey Component for the Optical Data Router • Error free frequency up-conversion: – from 1559.0 nm to 1550.1 - 1555.7 nm λsig • Penalty: 3 - 5.5 dB at BER = 10-9 • Penalty partly due to: – unmatched filter before receiver – degraded OSNR due to high coupling losses WC-SOA MZI λsig & λj λj j = 1..8 κ SOA 1-κ • WC-SOA: 350 mA • MFL’s SOAs: 150 mA • 90-110 mA (array) InP SOA Array WC 4.0 mm Converted optical eye diagram at 40 Gb/s (20 ps/div) Laser 6.5 mm Photonics on CMOS Silicon- Exciting Option for the Future! Deposited Waveguide Oxide Underclad W Studs Gate Contact Gate Contact Pad Demonstrated Integration of Working CMOS devices with Deposited a-Si waveguide process Rapid Progress in Silicon Photonics A Novel Optical Equalizer Recently demonstrated a novel device that: Provides widely tunable bandwidth equalization using a single control voltage Can operate at multiple bit rates Can provide simultaneous equalization and dispersion compensation And, Filter fabricated completely in a commercial CMOS foundry CMOS-compatible photonics could reduce system cost, enable new design paradigms, and create novel services For more info see - D.M. Gill et. al., CMOS Compatible Guided-Wave Tunable Optical Equalizer. Session: OTuM6 – Silicon Photonics II DARPA 40-Gb/s All-Optical XOR Operation Using a Hybrid Mach-Zehnder Interferometer • XOR Application • XOR operation A B A⊕B 1 1 0 1 0 1 0 1 1 0 0 0 -Pattern matching -Parity checking -Optical label processing -Pseudo-random bit sequence generation • 40Gb/s XOR eyes • 40Gb/s XOR logic verification A B A⊕B 20 ps/div 50 ps/div Inuk Kung, et al, Bell Labs, Alcatel-Lucent Summary • The success of optical layer transport networks suggests exploration of next generation photonic switching and routing offers potential for future impact • The evolution to all packet converged networks is driving efforts to cost-effectively scale packet over WDM transport • Challenge to address conflicting requirements for packet transmission and packet switching • Exciting progress in exploring architectures and technologies for high-speed photonic switching for packet networks • Challenging and Exciting research opportunities with potential for high future network impact! www.alcatel-lucent.com
