The role of optics in parallel processing

The author has recently been involved in trying to predict the specific technical areas where optical technology will next make a major technical and economic impact in advanced computer systems. This paper discusses some of the overall issues and highlights two new examples which he believes are likely to be important on a fairly short timescale. Because both basic physics and known device technologies suggest that it is likely to be most efficient to use photons for transmission and electrons for switching, the paper concentrates on fixed optical interconnection links between processors with all switching in the electrical domain. Breakthroughs in low energy optical switching could alter this view