Algorithm for optimization of interdigital transducer in AOTF

The interdigital transducer is an important device element in acousto-optic tunable filter (AOTF) and the surface acoustic wave (SAW) propagates in lithium niobate (LiNbO₃) as a substrate in interdigital transducer. In the direction of x-cut y propagation in AOTF, the power-flux vector and propagation direction of the surface wave are not collinear, which decrease the RF-to-SAW waveguide coupling efficiency. In this paper, optimal program is proposed, giving the numerical calculation. We know that to improve the coupling efficiency the direction of interdigital transducer should be inclined about 4.5 in AOTF. The experiment shows a satisfactory result.