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“Nonlinear Real-Time Optical Signal Processing, Final Technical Report”
by A.A. Sawchuk, T.C. Strand, and A.R. Tanguay, Jr.
October 1, 1984
This report summarizes the results of a research program in nonlinear real-time optical signal processing. The program began April 15, 1981 and ended June 30, 1984. The research effort has centered on optical sequential logic systems and their use in digital optical computers, and on variable grating mode (VGM) liquid crystal spatial light modulators. As a part of this study, parallel and twisted nematic liquid crystal light valve (LCLV) devices have been used as a nonlinear element in a feedback arrangement to implement a binary sequential logic system. A computer generated hologram fabricated on an e-beam system serves as a beamsteering interconnection element. A completely optical oscillator and frequency divider have been experimentally demonstrated, and various circuit interconnection techniques have been explored. Variable- grating mode (VGM) liquid crystal devices that perform local spatial frequency modulation as a function of the incident intensity have also been investigated. These devices can be used for nonlinear processing by selection and recombination ion of these spatial frequency components. These devices have many interesting physical effects with useful applications in both analog and numerical optical signal processing. Results on the physical modeling of VGM devices are given, with particular emphasis on experimental measurements of the Jones matrix describing polarized light propagation through the VGM cell. The program was performed with the cooperation of the Hughes Research Laboratories of Malibu, California.