An All-optical Ring Network With Past Tunable Sources

WDM technology and optical amplifiers have opened a new frontier for all-optical packet switched networks. However, several of the recently proposed WDM network architectures require as many wavelengths as the number of nodes attached to tlie network (see [a] for a survey). This resu1t.s in a dedicated wavelength channel for any node for either transmission or reception. These approaches might fall short when a relatively large number of nodes must be interconnected, due to c,urrently available optical technology, whic11 severely limits tlie maximum number of wavelengths in the system. We present a novel network architecture, named Daisy, that combines an N-frequency WDM approach with space diversity and time division access to interconnect up to N' nodes. 2 N fibers connect the nodes in a physical ring topology. Each node is assigned a dedicated logical cl~annel for reception operation. Daisy makes use of fast tunable transmitters and fixed receivers, and routes the light signals thoughout tlie network with passive optical components available today. Moreover, in Daisy routing is done so that a logical mesh configuration is realized over the ring physical topology. This configuration allows for a reduced maximum insertion loss encountered by packets, which in turns leads to a reduced amount of amplifier noise seen at the receiver.