Wavefront and polarization effects in actively tunable thin-film resonators for beam alignment in optical interconnects

Thin-film resonators operated at an oblique incidence angle produce significant spatial shifts of incident low divergence coherent beams based on the resonance-dependent effective group propagation angle. We investigate a single-layer resonator tuned by Joule heating and thermal expansion of the resonator cavity to allow for active beam position control. Operated in reflection on a right-angle glass prism, it is suitable for integration in optical interconnect networks and couplers to enable active beam alignment. The effects of polarization, beam divergence and wavefront aberrations are analyzed both in simulations and experiments.