Acousto-optic tunable wavelength and selective packet filter by simultaneously launching of acousto-optic waves of different frequency for TE–TM mode conversion in diffused optical and acoustic waveguides

Abstract

Optical filters employing acousto-optic polarized mode conversion techniques are implemented to demonstrate the filtering, selection, and switching of packets of wavelength multiplexed optical channels in LiNbO3 diffused optical waveguides. Geometrically tilted and chirped digital electrodes of the metallic interdigital transducer are used to excite acoustic surface waves for phase matching of the optical transverse electric (TE) and transverse magnetic (TM) guided modes, hence optical field coupling and transfer and filtering. By simultaneous launching of acoustics waves, the selection of wavelength channels can be made. A tuning range of >250 nm and that of the passband from <1 nm to >150 nm can be achieved with selectivity of optical channels of different wavelengths.