Abstract

Noncollinear, coplanar acoustooptic Bragg-interaction involving surface acoustic waves (SAW) and guided optical waves has been a subject of considerable interest because the resulting devices are compatible with future integrated/fiber optic systems (1). However, results of our previous study have shown that the bandwidth of a device using a single SAW is rather limited. For example, a bandwidth of only 45 MHz is possible for a device using Y-cut LiNbO₃ out-diffused waveguide of 7 μ penetration depth in which the acoustic aperture is 0.5 cm and the acoustic center frequency is 380 MHz (2). Recently, we had explored two device configurations utilizing multiple SAWs, namely, tilted and phased SAWs, which are capable of providing a substantially larger device bandwidth, and have reported some preliminary results (2,3). The first wideband device configuration employs multiple interdigital transducers which are staggered in their center frequency and tilted in their propagation axis (2). The second wideband device configuration employs multiple interdigital transducers of identical center frequency and propagation axis but having a specific step height between adjacent transducers (3).

© 1976 Optical Society of America