Picosecond Integrated Optical Logic

The concept of all-optical computing usually implies two-dimensional arrays of optical bistable logic elements interconnected by a lens imaging between them. The approach discussed here uses all-optical nonbistable devices with integrated optical wiring instead of bulk optics. It should provide most of the architectural flexibility of current electronic IC-based computers and be much faster. This article discusses first the advantages of its wiring over that of a lens-based system, then shows a method for achieving this integrated optical wiring. Next, it examines the properties of nonlinear optical materials and shows that a particular effect, the quantum well envelope state transition (QWEST), has the required properties. Finally, it outlines a method for creating an all-optical computer with 5- to 10-picosecond logic gates and gigabit memories.