Thickness dependence of acousto−optic diffraction efficiency in ZnO−film optical waveguides

The thickness dependence of the efficiency of the Bragg diffraction between the same optical modes (TE0→TE0, TM0→TM0) by acoustic surface waves in ZnO−film optical waveguides is investigated at an acoustic frequency of 130 MHz and a film thickness from 0.6 to 8.0 μm. It is observed that the efficiencies for both the TE0 and the TM0 modes vary more than 2 orders of magnitude with the film thickness.