Accession Number : ADA324598

Title :   Optical Neural Networks Based on Distributed Holographic Gratings.

Descriptive Note : Final rept. 30 Sep 92-28 Feb 96,

Corporate Author : HUGHES RESEARCH LABS MALIBU CA

Personal Author(s) : Owechko, Yuri

PDF Url : ADA324598

Report Date : 13 AUG 1996

Pagination or Media Count : 94

Abstract : This final report describes research in optical neural networks performed at Hughes Research Laboratories under a three year DARPA sponsored contract the advantages of optics for neural network implementations, including high storage capacity, connectivity, and very fine grained parallelism, was demonstrated. The optical neurocomputer developed under this program is based on a new type of holography which we call multiple grating holography, in which this approach reduces crosstalk and improves the utilization of the optical input device. In addition, this optical neurocomputer is the first and, to the best of our knowledge, the only one which is programmable and capable of implementing a wide variety of neural network models without any hardware adjustments. Successfully implemented neural networks included the Perceptron, Bidirectional Associative Memory, Kohonen, and backpropagation neural networks. Up to 10(4) neurons, 2 x 10(7) weights, and processing rates of 10(8) connection updates per second were achieved. Under this contract, we built an optical neurocomputer which utilizes a laser diode light source operating at 830 nm. This allowed us to reduce the size of the system. We also developed a new method for representing bipolar neural weights using coherent detection.

Descriptors :   *NEURAL NETS, *HOLOGRAPHY, *ARTIFICIAL INTELLIGENCE, ALGORITHMS, SIGNAL PROCESSING, COMPUTERIZED SIMULATION, ELECTROOPTICS, COMPUTER PROGRAMMING, COMPUTER ARCHITECTURE, PARALLEL PROCESSING, OPTICAL COMMUNICATIONS, LIQUID CRYSTALS, GRATINGS(SPECTRA), INFRARED IMAGES, ASSOCIATIVE PROCESSING, PATTERN RECOGNITION, OPTICAL CIRCUITS, OPTICAL PROCESSING, BUFFER STORAGE, CROSSTALK, BIPOLAR SYSTEMS, DIODE LASERS.

Subject Categories : Cybernetics

Distribution Statement : APPROVED FOR PUBLIC RELEASE