Abstract

Two types of photonic processors for generating the properly phased signals for a dynamically steered phased-array antenna are presented. Both methods make use of a class of spatial light modulator known as a deformable-mirror device (DMD). These devices can be envisioned as an N × N array of mirror elements, each capable of (computer-controlled) independent motion that is typically on the order of optical wavelengths. Varying this optical path length produces a substantial rf phase shift through photomixing. Because the number of elements in a DMD can be large (each DMD element corresponds to an array element, the highly directive antenna radiation patterns necessary for radar applications can be readily achieved. It is further demonstrated that a DMD-based system can be used to synthesize a variable rf delay line. Continuously variable true time delay in the rf regime has never been previously obtained, and, as such the scheme presented represents a significant contribution to the rf/microwave community as a whole. Experimental results that demonstrate both systems' performance are presented.

© 1990 Optical Society of America