Dynamic holographic interconnects with analog weights in photorefractive crystals

A photorefractive interconnect system with coherently erasable synapses (PISCES) is described. Comparing holographic erasure by intensity and phase modulation of the writing beams, we find that the timeaverage technique is most amenable to system implementation. Calculations derived from a simple model of diffraction show that it is possible to find configurations that maximize the interconnection capacity. The PISCES includes Fresnel zone plates for spot array generation, amplitude and phase spatial light modulators based on liquid crystal technology, and detector arrays, in addition to the photorefractive crystal. Alternatives for each of these elements are described.