Abstract

Phase-conjugated light waves are known to reverse phase distortions in media with negligible absorption or for paraxial beam propagation.¹ We examine here a different case in which a volume conjugating medium is itself imperfect, possessing phase distortions and a conjugating efficiency dependent on grating spatial frequency. We show theoretically that for multiplexed signals, cross-talk-free phase conjugation is obtained only for negligible spatial-frequency dispersion and a phase-conjugated reference wave. We further present experimental results in a severely striated sample of photorefractive strontium barium niobate; using a phase-conjugated reference wave, we demonstrate the alleviation of distortion² and the elimination of cross talk between closely spaced angularly multiplexed signals.

© 1992 Optical Society of America