Details of an investigation of a new type of electro‐optic multimode waveguide modulator or switch are reported. The device makes use of the concept of imaging in a multimode waveguide. Simultaneous switching of a few low‐order modes is obtained electro‐optically by nonuniform modulation of the refractive‐index profile of the active waveguide section. Small fabrication tolerances can be compensated for by electrical means and the device can be realized in various sizes and configurations for easy and efficient coupling to lasers, fibers, and other components. Modulation, switching, and power division have been demonstrated in waveguide devices of various widths and lengths fabricated on Ti‐diffused LiNbO3. Coupling losses as low as 0.5 dB have been observed and extinction ratios of 13–20 dB with 20–80 V drive have been obtained.