Multichannel Bragg Cells for Optical Computing Applications

Abstract

Acousto-optic Bragg cell devices currently provide the most effective way of imparting electrical information in real-time onto a light beam. Multichannel Bragg cells, with individually addressable electrodes on the same transducer substrate, extend the power of optical processing in a compact package to optical computing applications such as twodimensional optical switching and matrix-vector processing. The design of the cell, with the placement of multiple electrodes in close proximity on a common acoustic substrate, is constrained by crosstalk and thermal requirements not found in the design of a single-channel device. These constraints arise from the desire to place the electrodes as close as possible to maximize spatial duty cycle without creating unacceptable adjacent channel crosstalk and optical beam distortion. In this paper we discuss multichannel Bragg cell design principles and the use of RF stripline techniques and acoustically anisotropic acousto-optic materials with high thermal conductivity to achieve high multichannel cell performance. We describe several high performance Gallium Phosphide multichannel Bragg cells which employ these design techniques. We contrast the performance of these cells with devices manufactured commercially in the United States as well in the Soviet Union. Finally, optical computing systems using multichannel Bragg cells for switching and processing are discussed.