Acoustooptic interaction in a planar acoustic waveguide.

Acoustooptic interaction as well as the characteristics of both the longitudinal and the flexural modes of guided acoustic waves in an isotropic planar acoustic waveguide have been investigated theoretically. Material parameters for the SF-59 dense flint glass have been used in numerical calculations as an example. The interaction between L(1) longitudinal mode and an optical beam through the center of the acoustic wave-guide has been studied with particular detail and is compared with bulk acoustooptic interaction. It is found that the presence of acoustic boundaries results at nonuniform and frequency dependent acoustooptic interaction, unless the acoustic waveguide is made sufficiently thin. Substantial reduction in device driving power is possible using guided acoustic wave technology, due to the small cross section of the acoustic wave-guide.