Light propagation and acousto-optic interaction in a LiNbO3 spherical waveguide

Abstract

Propagation, guiding, collimation, and focusing of a light beam at 6328-Å wavelength in a LiNbO3 spherical waveguide as well as acousto-optic diffraction in such a waveguide using the surface acoustic wave centering at 245 MHz have been accomplished for the first time. Near diffraction-limited characteristics were measured in the incident light and the diffracted light was shown to preserve this desirable characteristic. Light beam scanning and various rf signal processing experiments including spectral analysis, correlation, and convolution were carried out with encouraging results. The potential advantages of the resultant spherical waveguide acousto-optic signal processor modules over the planar waveguide counterparts are also discussed.