Firehose Architectures for Free-Space Optically Interconnected VLSI Circuits

Free-space optical interconnects will soon be able to provide input/output bandwidths to a VLSI chip in excess of a terabit per second. The successful application of this technology to parallel distributed processing systems depends on the need for high-bandwidth interconnects and the ability of the architecture to sustain a stream of data at these bandwidths to the processing elements. We review examples of computational tasks that require scalable input/output, that is, computations where the I/O bandwidth of a processing element must grow in proportion to its computational bandwidth. We present several classes of optoelectronic architectures that can support a high-bandwidth data firehose, and mention applications in switching, FFT, sorting, matrix-vector processing, database search, and processor-to-memory interconnect.