Abstract

Multichannel bulk acoustooptic Bragg cells have found wide applications in real time optical signal processing and optical computing. Modern cells are designed for wideband signals and with closely packed transducers. Therefore, interchannel crosstalk and phase tracking capability have become the performance issues of Bragg cells to be used in applications such as the phase array antenna processing and optical computing. In a conventional multichannel Bragg cell, the crosstalk is caused in part by the rf interference and, in part, by the acoustic wave's diffraction spreading. In some typical cells, measurements¹ have shown that the crosstalk level is about −30 dB. Recently, a unique 64-channel, GaP Bragg cell, operated at 400 MHz, was fabricated with the self-collimated mode, in that the diffraction spreading was compensated by the self-focusing effect of the acoustic wave to reduce the crosstalk effect. The phase tracking capability was also considered in the design by equalizing the electrical leads. In this paper, we present detailed measurements of the crosstalk and the characterization of the phase tracking performance.

© 1989 Optical Society of America