Optical-fiber grating-based beamforming network for microwave phased arrays

A new photonic-based beamforming network that can realize a large number of simultaneous and independent beams in a wide-band phased-array antenna, and which eliminates optical beat-noise interference is presented. It is based on discrete and chirped Bragg-grating true-time delay elements and photodetector arrays at each beam port. This achieves a highly parallel delay-processing structure for signal equalization and eliminates the fundamental optical beat-noise limitation to the realization of large array sizes. Results show a very substantial reduction in the number of interconnects required of 98.4% for a 512-beam array and 99.2% for a 1024-beam array, in comparison to conventional beamforming techniques.