N. H. Tran

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.

Generation of microwaves by mixing two optical frequencies in a nonlinear crystal: a novel approach to high-bandwidth optical mixers

Optical mixing of waves separated in frequency by many gigahertz can be accomplished by allowing the waves to mix in a nonlinear medium to generate microwave difference frequencies. This basis for high-bandwidth optical mixers is demonstrated by mixing optical frequencies approximately 4 GHz apart of a pulsed dye-laser beam at approximately 660 nm in a LiTaO(3) crystal to produce readily detectable microwave power at approximately 4 GHz.