Asynchronous optical packet routers.

摘要

Asynchronous optical packet switching is presented as an alternative to current core electronic routers used for high-speed Internet traffic. Current core Internet routers process all information electrically at the bit-level. As bandwidth and capacity increases, the need for higher speed electronics leads to increases in power consumption and footprint. In label swapped optical packet switching, forwarding information and data are separated into low bit-rate optical labels and high bit-rate optical payloads. This allows for the use of low frequency electronics for processing label information while transparently forwarding high bit-rate payloads optically at low switching speeds. The use of low speed electronics and further integration of photonic devices could reduce power and footprint limitations of scaling high capacity core data routers.;Asynchronous operation of routers is the key to scaling large networks where multiple independent nodes are used, each with their own packet and bit-level clock sources. Prior to this work, there has been little published on asynchronous optical packet switching. Asynchronous operation causes inherent timing uncertainties on the clock and packet-level due to the frequency drift between plesiochronous clocks. These uncertainties create unique challenges to optical technologies and architectures.;In this work, the first asynchronous optical packet router is demonstrated. The architecture and optical technologies of the router are discussed and performance measurements presented. The impact of the performance of the optical technologies used in the router is a key aspect of this work. Synchronization, buffering, and forwarding of asynchronous optical packets are performed using photonic integrated technologies. Optical packet synchronizers are used to dynamically align incoming packets to local timeslots for efficient buffering and switching. Multiple optical buffers based on integrated InP technology are used to resolve contention of packets destined for the same port at the same time. Forwarding of optical packets is done through the use of monolithically integrated field-based packet forwarding chips to route packets to different ports. Finally, time and wavelength division multiplexed asynchronous optical packets originating from multiple independent sources are detected and analyzed on a per packet basis using a custom burst mode receiver.