QUADRATIC PROCESSING AND NONLINEAR-OPTICAL PHASE RECTIFICATION IN NOISE-REDUCTION

Optical spatial phase rectification by limiting quadratic processing i n photorefractive two-beam coupling is proposed and demonstrated. We u se this limiting quadratic processor to reduce complex multiplicative noise. The principle of compansion (compression and expansion) from se rial communication theory is introduced for the first time to our know ledge in parallel optical signal processing. In addition the effect of two-beam coupling compression on the efficiency of beam cleanup is il lustrated experimentally and optimized through computer simulation.