A broad-band LAN using a photonic TMS.

An active star architecture is shown to provide efficient broad- band communications in a photonic Local-Area Network. The effective average data rate over the virtual channel between every pair of terminals is proposed as a figure of merit for LANs. Connectivity at the hub of the star is provided by a time-multiplexed permutation switch. A new species of switch architecture, called a dilated slipped banyan network, is shown to be appropriate for an implementation in lithium niobate. Of an N-to-N switch is column-controlled by a Gray Code with even parity and cycles through N configurations, then it provides full connectivity, has an exclusive-OR relationship among port numbers and time-slots, and all its port number permutations are paired. A 16-terminal LAN, with 100 Mbps between every pair of terminals, is described, that is feasible today. More futuristic examples, serving as many as 1024 terminals, are possible by time-multiplexing or double-hop architectures.