Optical information systems

Optical information systems

Systems that use light to process information. Optical information systems or processors consist of one or several light sources; one- or two-dimensional planes of data such as film transparencies, various lenses, and other optical components; and detectors. These elements can be arranged in various configurations to achieve different data-processing functions. As light passes through various data planes, the light distribution is spatially modulated proportional to the information present in each plane. This modulation occurs in parallel in one or two dimensions, and the processing is performed at the speed of light. Optical processors offer various advantages compared to other technologies: data travels at the speed of light; all data in one-dimensional and two-dimensional arrays are operated on in parallel; multiple planes of data can be processed in parallel by various multiplexing schemes; it is possible to have large numbers of interconnections with no interaction (which is not possible with electrical connections); and power dissipation is less and size and weight can be less for optical processors than for their electronic counterparts. See Concurrent processing

In practice, the processing speed is limited by the rate at which data can be introduced into the system and the rate at which processed data (produced on output detector arrays) can be analyzed. The reusable real-time spatial light modulators used to produce new input data, filters, interconnections, and so forth, are the major components required for these optical information-processing systems to realize their full potential. Spatial light modulators convert electrical input data into a form suitable for spatially modulating input light, or react to an optical input and generate a different optical output. The manipulation of the light passing through the system is controlled by spatial light modulators, lenses, holographic optical elements, computer-generated holograms, or fiber optics. Four major application areas are image processing, signal processing, computing and interconnections, and neural networks. See Neural network, Optical modulators