Abstract

Self-routing is employed in fast packet switching systems to increase throughput, which in general is limited by speed of the switch control technology. Optical processing has successfully improved throughput by increasing the processing rate of header information.¹ In this paper an architecture is proposed whereby optical processing controls a photonic Batcher-Banyan network. Both switch and control architectures are compatible with current integrated-optic devices. Routing information is coded by wavelength-division multiplexing and processed at the switch in real time with bandpass filters.² In the sort stage, filters remove routing information, and the weighted sums of routing channels are compared to produce the sort function. The permutation stage consists of crosspoints with prefilters that remove a specific wavelength, analogous to bits in a serial header. Synchronization based on switch setup time and group delay between control signals and data are important issues in this scheme. Channel utilization is calculated to be better than 98% for 155 Mbit/s, 43 byte cells transmitted through a 32 × 32 switch up to 100 km. The number of cross-points is 3/2(N log₂ N) for the Banyan switch and 1/2[(log₂ N)³ + (log₂ N)²] for the Batcher sorter.

© 1990 Optical Society of America