Comparison between optical measurement and numerical analysis of diffraction effect of surface wave on SAW devices

摘要

The optical measurement results of the diffraction effect of the surface wave from uniform IDT on 128° Y-X LiNbO3 substrate and from chirp IDT in the dispersive delay line on Y-Z LiNbO3 substrate are compared with the simulation results of using the Fresnel integration by the parabolic anisotropy approximation. As the results, it has been shown that the simulation results are corresponding to the experiment results well when the anisotropic parameter calculated from the material constants of G. Kovacs et al or J. Kushibiki et al is used, and also explain well the asymmetrical diffraction effect of the surface wave excited from chirp IDT toward right and left direction in the dispersion delay line.