OPTICAL NEURAL NETWORK AND METHOD

An optical neural network stores optical transmission weightings as angularly and spatially distributed gratings within a phase conjugate mirror (PCM), the PCM using a stimulated process to generate a phase conjugated return beam without separate external pump mechanisms. An error signal is generated in response to differences between the actual and a desired output optical pattern, and is used to adjust the PCM gratings toward the desired output. One or more intermediate image planes may be employed along with the input and output planes. The input and intermediate planes, as well as the error signal, are preferably displayed on the surface of a spatial light modulator. The output optical signal is transduced into an electrical format for training the neural network; with the error signal also generated electrically. A significant increase in neuron and interconnection capacity is realized, without cross-talk between neurons, compared to prior optical neural networks.