Abstract

There has been much Interest recently in the use of photorefractive materials as suitable nonlinear media for a variety of optical information processing applications, including phase conjugation, edge enhancement, spatial convolutlon/correlation, image transmission through optical fibers, laser fiber gyroscopes, and associative memories.¹’² Early on it was recognized that, by temporally encoding the pump waves to a four-wave mixer, a modulated phase-conjugate wave can be realized. Conjugators using this technique have been demonstrated in several areas, including retrophase modulators,³ as well as O-swItched⁴ and mode-locked⁵ phase-conjugate resonators. In all these schemes, the modulation was provided via optical means, that is, external to the conjugator medium.

© 1986 Optical Society of America