A Digital-Optical Hybrid Correlator

Abstract
A Digital-Optical Hybrid Correlator with the capability of processing pulse doppler and wideband radar signals has been developed based on the correlation properties of an optical phased array. This hybrid system retains the flexibility of digital technology for signal storage and registration, and the speed of coherent optical technology for performing the signal correlation. Two phased-array modulators have been developed. The Membrane Light Modulator is a mirror whose surface can be deflected in localized areas by electrostatic forces. The multichannel crystal modulator employs the electro-optic properties of lithium tantalate to achieve phase modulation. Both modulators have been used to perform optical phased-array beam steering. Pulse doppler and wideband radar signals have been processed by the hybrid correlator. The system's capability to perform two-dimensional correlation of frequency diversity radar waveforms has been demonstrated.