State-by-State Report on Permanent Public Access to Electronic Government Information

A coupler for optical guided waves is described which is electronically switchable and wherein light traveling in a fiber optic waveguide can be coupled into a thin film waveguide. The coupler consists of a substrate which in one embodiment is triangular in shape, with a thin film waveguide and an acoustic transducer on one surface thereof. The transducer is designed to produce an acoustic wave across the surface of the substrate and beneath the thin film waveguide. The output light from the optical fiber is introduced via a lens into a Fabry-Perot cavity formed by placing two high reflectivity mirrors located on the other two sides of the substrate. The light from the optical fiber is reflected back and forth in the cavity by being reflected from the surface on which the thin film is located. When the acoustic transducer is operated at the proper frequency, the light in the cavity is coupled into the thin film waveguide. Another embodiment is also shown wherein the fiber optic is connected directly into the substrate which is not triangular in shape.