Principles of a resonant cavity optical modulator.

We describe the principles of a resonant cavity optical modulator capable of modulation frequencies in the 10-GHz range. The dispersive properties of waveguides are used to achieve phase matching of the optical and rf waves, which differ in velocity by a factor of 3 in bulk electrooptic materials. The difference in propagation velocities also allows us to form a rectangular cavity with two opposite sides open through which the optical beam may be easily passed. A modulator employing this design is thus both efficient in its use of rf power and is easily optically aligned.