We describe a high‐speed deflector‐modulator based on an electro‐optically induced thick phase grating in optical waveguides of single‐crystal epitaxial ZnO film on Al2O3substrates. 40% of the beam is diffracted into first order with response times of 3 nsec. The extinction ratio in the deflected beam is greater than 95%. We predict 80% diffraction, response times of < 1 nsec, and power requirements of approximately 1 mW/MHz for an optimized geometry.