Abstract

We have demonstrated a new design for an optical processing unit with functionality similar to that of a previously demonstrated unit¹ and have examined its correspondence to a tolerance model. The logic unit consists of two ZnSe thermal bistable gates, which employ external absorption so that they may be operated with semiconductor lasers. Each of eight two-input binary logic functions could be reliably selected by adjusting the switching thresholds of the two gates with separate control lasers. We have adapted a recently developed tolerance model² for bistable gates, and we find that it matches the observed performance closely enough to permit the model to be used to design more complex circuits. However, the thermal gates used exhibit "memory" effects that limit the applicability of the model. With the development of improved gates, either thermal or electronic, this model will provide a systematic approach to the design and characterization of digital optical processing systems.

© 1990 Optical Society of America