ENERGY EFFICIENT ALL-OPTICAL SOA SWITCH FOR THE “GREEN INTERNET” Yuri Audzevich, Michele Corrà, Giorgio Fontana, Yoram Ofek, Danilo Severina Università degli Studi di Trento, Dipartimento di Ingegneria e Scienza dell’Informazione, via Sommarive 14, POVO, Trento ITALIA

Introduction The possible commercial success of traditional “all-optical switching” depends on the solution of several difficult challenges: like building –optical buffers, –optical header processors, and –optical systems in general. When all these problems will be solved, hundreds of Gb/s link speeds will become standard. Unfortunately this is something that might not happen very soon within the current network asynchronous IP switching paradigm. An alternative switching paradigm has been recently developed that predetermines the routing configuration of network switches according to SCHEDULED traffic using “freely available” global time or UTC (coordinated universal time) from a variety of sources on earth and in space[1]. Better than 1us accuracy.[1] The novel paradigm, called Time Driven Switching (TDS) or Fractional Lambda Switching (FLS), allows the efficient use of all- optical switches RIGHT NOW because it does not require buffers and header processing.

A TDS Network (simplified) Like Circuit Switching (physical-zero latency), But you only need to OWN the fraction of the circuit where the datagram is TEMPORARILY located. Precise synchronization is required. Shown to work, see literature. Specific hardware: 1)Time Driven servers 2)Time Driven switches Network: 1)TCP/IP can be adopted 2)Gb Eth optical can be adopted

Pipelines are deployed to increase efficiency: Optimal method - independent of a specific realization Factory (automotive) / computers (CPU) Internet Pipeline thanks: GPS/Galileo/multitude of other sources Time frames as virtual containers for IP packets –Thus, no header processing –T f accuracy of 1µs is sufficient Pipeline Forwarding with UTC Factor of 20 Lower Cost / Premium Services Time Cycle Time Cycle Time Cycle 79 UTC second with 80k Time-frames Time-of-Day or UTC 0 beginning of a UTC second 1 beginning of a UTC second

Current Networking Test-bed Setup TDS switch Streaming Media Source Pipeline Forwarding router 25 km Optical Fiber GPS/GALILEO Streaming Media UTC 1PPS UTC 1PPS O-E E-O O-E: Optical-to-Electrical (analog) E-O: Electrical-to-Optical (analog) Arbitrary Distance Arbitrary Distance Streaming Media E-O O-E 25 km Optical Fiber TDS All-optical Switch FPGA GPS FPGA GPS FPGA GPS UTC 1PPS UTC 1PPS

All Optical Switch Design

Components QPhotonics SOA1550 ComBlock COM1300 PCMCIA FPGA Ublox LEA-4T GPS Timing Receiver Xilinx Spartan-3 XC3S400-4 FPGA features 400K system gates including 288Kbit of dual port memory and 16 dedicated 18x18 multipliers. 32MB SDRAM for use as elastic buffer

Components

Complete Optical Switch

SOA Controller

GPS Timing Panel

Operating Parameters Panel

Switch Scheduling Panel

Eye Pattern Eye pattern of GbEth transmitter->25km fiber->SOA (25%Inom)->25kmfiber->RX Inom = 200 mA

Eye Pattern Eye pattern of GbEth transmitter->25km fiber->SOA (35%Inom)->25kmfiber->RX

Eye Pattern Eye pattern of GbEth transmitter->25km fiber->SOA (50%Inom)->25kmfiber->RX

Energy Efficiency In our 2x2 switch each output fiber requires an average of 1.2 V*100 mA= 120mW of power for SOA power supply. The requirement can be scaled up for larger switches operating within fractional lambda switching and TDS principles. 128x128 Banyan switch will require 4x7x64/128=14 SOA per output fiber. To avoid switch blocking the number of SOA simultaneously active per output fiber has to be 7. At 10 Gb/s this is 7*120/10 mW/Gb/s = 84 mW/Gb/s that clearly is only 8.4 mW/Gb/s if the switch is operated at 100Gb/s. By comparison high-end traditional switches require abut 20 W/Gb/s per output fiber. – We have three orders of magnitude lower power!

Conclusion & The Future We described a high performance all-optical switch implementing the fractional lambda switching paradigm with time driven scheduled switching. The switch has been successfully tested with BERT at 1.25 Gb/s and with UDP multimedia streams with Gb Ethernet interfaces. The switch can scale to very high capacity and provide an energy efficient switching solution for the future green internet. This first combination of TDS with SOA switching is the first small step; much more efforts and funding should be directed towards this new technology for a better characterization of existing hardware and future experimentation on a larger scale, including the important combination of WDM-TDS. INTERNET KeyWORDS: IPFLOW TRENTO