WIDEBAND AMORPHOUS-SOLID DEBYE-SEARS LIGHT MODULATORS FOR ARRAY-ANTENNA PROCESSORS
COLUMBIA UNIV NEW YORK ELECTRONICS RESEARCH LABS
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The use of fused-silica Debye-Sears light modulators in electro- optical array-antenna processing is investigated theoretically and experimentally, with the result that a significant gain in signal-processing capacity, over that which can be achieved with liquid light-modulators, is shown to be possible. The operation of the fused-silica light-modulator in the neighborhood of 80 MHz is investigated. Transfer characteristics between electrical excitation and spatial modulation of light wave front are found to be linear, first-order light-intensity distributions are measured and found to be nearly ideal, and measurements of bandpass characteristics show that light- modulator bandwidths which are 50 percent of resonant transducer frequency are easily achieved. The effects of internal refraction on the electro-optical processor are determined. The effects of cross coupling on closely spaced light- modulator channels are also investigated experimentally and results are found to be consistent with evaluations of signal-processing capacity. Large aperture- bandwidth array-antenna processing is shown to result in non-separable optical transmission functions for which the diffraction patterns are determined here for the first time. It is shown that noise degradation would not be a limiting factor in the elctro-optical processor.
- Electrooptical and Optoelectronic Devices