A role for optics in future parallel processing

Abstract

There is real opportunity for optical computing, especially free-space optical communication, to improve the performance of supercomputers that exploit parallel processing techniques. In order to seize this opportunity, this paper reviews some of the needs of parallel architectures that appear hard to satisfy with standard electronic techniques and that may be more ameanable to optics. The ability to vary the focus of a free space optical beam lets one choose between sending a signal between two points in a narrow focus or to broadcast a signal from one source point to many target points with a wide focus. Electronic communication has mainly considered the former, but it is known that a little bit of broadcasting can go a long way in improving the performance of many applications. Even when one considers the power comsumption, e.g.broadcast is done at a lower data rate, performance may still be improved. We describe the standard techniques for broadcasting in parallel processors and how they are employed in current applications. Using these results, it becomes more clear where optics may help.