Thin Film Optical Switch.

This report, together with three previous quarterly reports, presents the design, development, fabrication and evaluation of a wideband optical switch based on the deflection of two dimensionally confined beams by electro-optically controlled phase grating. The waveguide medium is Ti-diffused LiNbO3. An interdigital electrode is placed on the overlapped region of two crossed channel waveguides. When a voltage is applied to the electrode, a Bragg phase grating is formed so that the optical beam in one channel waveguide is deflected into the opposite one. In order to interface the switching device to single mode optical fibers, 4 micrometers wide single mode channel waveguides are employed at the input and output ports. These waveguides are expanded adiabatically through slowly tapered sections into wide multimode channel waveguides (30 micrometers) that intersect in the grating interaction region.