Abstract

We demonstrate ring and star architectures for dynamical interconnection of data processors. Consider a number of processors, each with an optical transmitter and receiver, interconnected by a ring of multimode fibers, using passive couplers for input and output at each station on the ring. Each transmitter includes a means for encoding a set of orthogonal spatial patterns on the transmitted beam. The output at each station, after propagation part way around the ring, is a speckle pattern which is uniquely defined by the injected spatial pattern. To program the interconnections the speckle patterns are used to write volume holograms in a photorefractive crystal at each receiver. Subsequently selecting a particular input spatial pattern results in diffraction only at the stations which have been programmed with that pattern. The interconnections can be reprogrammed in the write time of the holographic media, and switched at the update frequency of the spatial light modulator. Both fan-in and fan-out are possible. Ring and star networks with three stations have been constructed. Typical transmission losses and crosstalk to signal ratios are –21 and –25 dB, respectively.

© 1990 Optical Society of America