Integrable surface-emitting laser-based optical switches and logic gates for parallel digital optical computing

Abstract

We describe the recent advances in a monolithic optoelectronic technology based on the integration of two-dimensional arrays of cascadable optical switches and optical logic gates consisting of vertical-cavity surface-emitting lasers (VCSEL's) and heterojunction phototransistors or photothyristors. Different combinations of these components can perform optical switching, logic, memory, and regeneration. Latching, nonlatching, and bistable switches with high optical gain and contrast are demonstrated by using a single GaAs-AlGaAs epilayer design along with single-stage Boolean optical logic functions: AND, OR, IDENTITY, INVERT, NAND, NOR, and XOR. As an application to parallel, digital arithmetic logic, we describe a simple, compact, two-chip binary adder, which uses optical symbolic substitution and two-dimensional VCSEL-PNPN logic gate arrays.