Tunable Wavelength Based Photonic Architectures for the Dynamic Control of Phased Array Antennas

摘要

This report examines three novel photonic systems for controlling broadband phased array antennas. These photonic systems take advantage of recent advances in fiber Bragg gratings, high dispersion optical fiber and tunable wavelength laser technologies. The first system is a transmit/receive beamformer that uses fiber gratings arranged in a prism-like configuration. A proof-of- concept breadboard for controlling a three-element phased array antenna demonstrated high-resolution beamsteering over a 3.5 GHz bandwidth. Based on this discrete architecture, two other systems are proposed; a transversal filter and an optical packet encoder/decoder for optical data communication systems. The second system utilizes high dispersion optical fiber along with fiber Bragg gratings to achieve continuous steering for both transmit or receive. The system, dubbed a photonic crossbar switch, allows the independent routing of a wavelength-encoded signal from an arbitrary input port to an arbitrary output port. The third system, a modified version of the crossbar switch, is capable of broadband null steering. Measurements taken over a ten-percent fractional bandwidth on a three-element proof-of-concept system showed a uniform null depth of better than 40 dB across the entire band. The architecture presented is best suited for small antenna array applications, for example GPS-guided airborne munitions.