Optical Interconnection architectures for digital systems and processors

Abstract

We describe the use of bulk (3-D) optical systems in interconnection networks for electronic digital parallel processing and for telecommunications. More powerful computing architectures can be achieved through the use of parallel processors and the sharing of resources such as memory. Ideally, these elements must communicate through a dynamic, flexible interconnection network with a minimum of contention (message conflicts). A crossbar interconnection allows general communication without contention, but is has been difficult to implement large crossbars electronically due to VLSI technology limitations. For this reason, simpler interconnection networks having contention or suitable only for specialized applications have been developed. We describe some potential advantages of optical interconnection networks, including high signal bandwidth, low mutual interference, and parallelism. We present several implementations of electrically controlled generalized optical crossbar interconnection networks (having no contention and broadcasting capability) based on optical vector-matrix and matrix-matrix multiplier designs. These systems utilize acousto-, electro- or magnetooptic spatial light modulators (SLMs) as the active controlling element. We define important general parameters for electronic and optical interconnection networks and give a comparison of capabilities for many architectures. We also describe a separate all-optical digital sequential processor architecture which implements optically controlled interconnection networks.