California Institute of Technology

The United States of America As Represented by the Administrator of the

Gregory O Gheen

Li-Jen Cheng Cheng

Afshin Partovi

Optical processing using photorefractive GaAs and other compound semiconductor crystals (28) is achieved in a four-wave mixing configuration. Potential applications of optical processing include spatial light modulation, phase conjugation, correlation, convolution, edge enhancement, matrix multiplication, incoherent-to-coherent conversion, and many others. In particular embodiments, optical processing, matrix multiplication, and integrated semiconductor optical information processors are demonstrated. In the case of integration of semiconductors and optical information processors, a spatial light modulator (88) is fabricated on a surface of a compound semiconductor crystal to form an integrated device (86). The device uses the spatial light modulator to transfer electrical data into an optical form and then employs the photorefractive effect in the bulk for processing the data.

Optical processing in III-V and II-VI compound semiconductors

Spatial light modulation (22) in a III-V single crystal (12), e.g., gallium arsenide, is achieved using the photorefractive effect. Polarization rotation created by beam coupling is utilized in one embodiment. In particular, information (16)on a control beam (14) incident on the crystal is transferred to an input beam (10), also incident on the crystal. An output beam (18) modulated in intensity is obtained by passing the polarization-modulated input beam through a polarizer (20).

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Pasadena, CA, United States of America

Gregory O Gheen