COMPACT 4D OPTICAL NEURAL NETWORK ARCHITECTURE

THIS PROPOSAL ADDRESSES THE DEVELOPMENT OF MASSIVE OPTICAL INTERCONNECT CAPABILITY IN A COMPACT CONFIGURATION FOR IMPLEMENTATION OF GENERAL PURPOSE NEURAL NETWORKS. THE METHOD DESCRIBED IN THIS PROPOSAL MAY BE ABLE TO ACHIE 10(12) INTERCONNECTS BETWEEN TWO FULLY-POPULATED PLANES OF 10(6) STATES. PSALTIS HAS PROPOSED USING VOLUME HOLOGRAMS FOR 3D OPTICAL INTERCONNECTS BETWEEN TWO PLANES. THIS METHOD IS SUBJECT TO AN IMPORTANT LIMITATION. AN INTERCONNECT VOLUME N WAVELENGTHS ON A SIDE HAS A MAXIMUM OF N(3) "DEGREES OF FREEDOM" WHICH CAN BE USED TO SPECIFY INTERCONNECT WEIGHTS. THIS NUMBER IS LESS THAN THAT REQUIRED TO CONNECT TWO FULLY-POPULATED PLANES OF N(2) ELEMENTS. PSALTIS HAS SOLVED THIS PROBLEM BY USING PARTLY-FILLED INPUT AND OUTPUT PLANES. WE PROPOSE THE USE OF LASER WAVELENGTHS AS A FOURTH DIMENSION. N(4) INTERCONNECT WEIGHTS CAN BE WRITTEN IN A VOLUME MEDIUM PRODUCING THE DEGREE OF FREEDOM NEEDED TO CONNECT TWO TWO-DIMENSIONAL PLANES. OUR PHASE I GOAL WILL BE CHARACTERIZED THE PROPERTIES OF A 4D OPTICAL INTERCONNECT "BUILDING BLOCK" BASED ON CURRENT AND PROJECTED PROPERTIES OF SPECTRAL HOLE BURNING (SHB) MEDIA. THE PHASE II GOALS ARE (1) TO ADDRESS EXPERIMENTALLY THE KEY ISSUES ASSOCIATED WITH WRITING AND ERASING VOLUME HOLOGRAMS AT MULTIPLE WAVELENGTHS IN AN SHB MATERIAL, AND (2) TO DESIGN A COMPACT 4D INTERCONNECT DEVICE.