Controlling the self-frequency shift and intensity of oscillations with photorefractive crystals

A method for controlling the frequency shift and intensity of the oscillating beams in a new type of optical interferometry based on photorefractive four-wave mixing in a ring cavity is reported. It is shown that the application of a dc electric field onto the mixing crystal results in frequency detuning of the oscillating beams. In addition to its use as an optical frequency tuner, the field can shift the device's operating point when used as a gyroscope. The frequency tuning is also controllable by the ring's optical loss and the mixing crystal's efficiency and time constant.