Acoustic surface wave Δv/v waveguides on anisotropic substrates

Accurate measurements of the phase and group velocity dispersion curves have been made for Δv/v waveguides on $\text{(001)\hspace{0.17em}〈 110 〉\hspace{0.17em}}{\mathrm{Bi}}_{12}{\mathrm{GeO}}_{20}.$ The measurements are shown to be in good agreement with the results of a simple theory which includes the effect of substrate anisotropy. Results indicate that the acoustic energy is bound more tightly to waveguides fabricated on crystal orientations where anisotropy provides a reduced diffraction loss for unguided waves.