Electro‐optic multimode waveguide switch

A new and simple electro‐optic multimode waveguide modulator/switch that utilizes the concept of imaging in a multimode waveguide is described. Switching of a few low‐order modes is obtained electro‐optically by nonuniform modulation of the refractive‐index profile of the active waveguide. The device can be realized in various sizes and configurations, thus enabling easy and efficient coupling to lasers, fibers, and other components. Extinction ratios of 13–20 dB with 20–80‐V drive have been observed in several Ti‐diffused LiNbO3 devices fabricated to date.