Aoustic modulation of TM and TE waves in two-dimensional silicon phoxonic cavitiy

We investigate the photon-phonon coupling, based on both photo-elastic and opto-mechanical mechanisms, in a two-dimensional periodic structure exhibiting simultaneous photonic and phononic band gaps. The coupling takes place in a cavity defect in which the strong confinement of acoustic and optic waves enhances the acousto-optic interaction. We calculate the modulation of each photonic mode frequency by each phononic mode confined in the cavity and compare the acousto-optic interactions for both TM and TE waves. We also compare the strength of the photo-elastic and opto-mechanical effects in the different cases. Both mechanisms can be in phase or out of phase and produce additive or subtractive effects in the total acoustooptic coupling.