Two dimensional arrays of InGaAsIJnP based multiple quantum well surface modulators driven by standard high-speed CMOS have been demonstrated in experimental parallel optical interconnect and artificial neural processing systems. Transition times were fast enough for lOOMBit/s operation and the potential exists to increase array dimensions to include 100''s of devices and transmission rates to many GBit/s. Novel architectures employing computer generated holographic beam splitters and weight matrices outside the modulator and detector layers were employed.

A family of fixed and reconfigurable optical interconnection networks offering the potential of Terabit throughput are described. The designs are based on a bus architecture that combines space, wavelength and other multiplexing methods and have the following attractive features:- graceful growth; wide-sense non-blocking operation; low space switch crosspoint count; and simple control algorithm.

The potential for coherent detection to improve the receiver sensitivity and expand the transmission capacity of optical communications systems has now been demonstrated in a number of laboratories, but much remains to be done to develop systems for use in telecommunications networks. In the light of reported experimental results, this paper reviews the performance required of devices and components for coherent systems, and considers the developments needed to bridge the gap between laboratory demonstration and field application.