Design of a broadband acousto-optic filter using bulk acoustic wave beam steering with an interdigital transducer

Acousto-optic tunable filters are photonics devices whose operation is fundamentally based on crystal acoustics. One of the phenomena used to improve performances of bulk acousto-optic devices is acoustic beam steering. Here we present a complete analytical model, which covers bulk acoustic wave beam steering in crystals with phased-array excitation and Bragg phase matching of anisotropic acousto-optic diffraction. An interdigital phased-array transducer is proposed for laterally excited bulk acoustic wave generation enabling the effect of beam steering. The design of a paratellurite-based acousto-optic filter with extended transmitted optical wavelength range from 0.4 to 1.1μm is discussed and supported by numerical simulations.