Switched optical polymeric waveguide true-time-delay lines for wideband photonics phased array antennas

It has been realized that the lack of enabling technology of beam forming and steering devices significantly slows down the process of implementing wideband phased array antenna systems. In this paper, we present our research in developing an integrated electro-optic switched true-time-delay module as a broadband beam forming device for wideband phased array antennas. The unique feature of our approach is that both the true-time-delay waveguide circuit and electro-optic switching elements are monolithically integrated in a single substrate. As a result, this integration significantly reduces the device size while eliminating the most difficult packaging problem associated with the delicate interfaces between optical fibers and optical switches. Such a monolithic approach offers greater precision for the RF phase control than the fiber-delay-lines thanks to the sub-micrometer accuracy of lithography-defined polymeric waveguides. More important, the proposed optical switched true-time-delay network requires very low electrical power consumption due to the low power consumption of electrically-switchable waveguide gratings. Furthermore, the electrically-switchable waveguide gratings have a very fast switching speed (<50 mus) that is at least 100 time faster than any existing commercial optical switching matrix. Photonic phased array antenna based on optical true-time delay lines offers improved performance and reduced weight and power consumption over existing parabolic dish antenna presently used for communications.