SPACE-DIVISION OPTICAL STAR NETWORKS WITH DEFLECTION ROUTING

An optical star network is implemented bgy an MxM space-division cell switch to whichg M nodes are connected by dedicated fibers. Each node is equipped with an optical transmitter and an optical receiver. Deflection routng is used to simplify the structure of the central interconnect and the routing of packets within it. Deflected packets delivered to the wrong user are re-routed to the switchg. A multi-stage optical implementation of the central interconnect based on Sfuffle-Exchange stages made of 2x2 crossbar directional couplers is considered. The elementary beta swiching elements within the interconnect fabric contain either zero or one optical buffer. The number of stages n is varied from 1 to logM. The network topology thus evolves from a pure Shuffle Exchange network, which is multihop, to a potentially single-hop star network when the interconnect is complete (n=logM). It is shown how the drastic reduction of the hop count in the complete interconnect case allows both larger throughput and substantially lower loss as conpared to the multihop approach, making such topology an attractive candidate for a transparent optical implementation