Full-Vectorial Finite-Element Analysis of Acoustic Modes in Silica Waveguides

A finite-element code has been developed to study the vector acoustic modes in high index contrast silica optical waveguides. Detailed spatial variations of the transverse and longitudinal displacement vectors are shown for the bending, radial, and torsional modes. The variation of the frequency shift due to the stimulated Brillouin scattering and the overlaps seen between the acoustic and optical waveguides also are presented, together with the modal hybridness and modal dispersion.