OPTICALLY PRODUCED TRUE-TIME DELAYS FOR PHASED ANTENNA-ARRAYS

A device is described for generating true-time delays optically for mi crowave signals used in beam steering and beam shaping in phased-array antennas. The device can be adapted to provide delays from picosecond s to nanoseconds. A single, compact unit should provide parallel delay s for more than 64 independent antenna elements with a greater than 6- bit resolution. The time delays are produced by multiple reflections i n a mirror configuration with continuous refocusing. A single spatial light modulator selects independent optical path lengths for each of t he parallel antenna elements. Amplitude control for beam shaping can b e integrated into the device. The unit can be made rugged for harsh en vironments by use of solid-block construction. The operation of the tr ue-time delay device is described, along with the overall system confi guration. Preliminary experimental data are given. (C) 1997 Optical So ciety of America.