Abstract

Acoustic surface waves (ASW) have been used to achieve convolution by a number of researchers.^1-10 Use of acoustic optical (AO) interactions for convolution in the bulk medium was reported by Damon et al. and Squire et al.^11-13 The signal-to-noise ratio and the dynamic range of the bulk AO convolver are low because the AO interaction is not very efficient. Bragg diffraction of optical guided waves (OGW) by ASW can be very efficient in thin-film waveguides, e.g., an As₂S₃ film deposited on top of a LiNbO₃ substrate.^14-15 Convolution by guided AO interaction may yield large dynamic range or time-bandwidth product. More importantly, it will allow us to carry out signal processing of the optical energy in thin-film waveguides which may have many applications in the single-mode optical fiber communication systems of the future. We report here the results obtained in an OGW-ASW convolver using the Ti in-diffused LiNbO₃ and As₂S₃ waveguides. This is the first guided-wave AO signal processing that has been observed experimentally.

© 1976 Optical Society of America