Flexible True-Time-Delay System with Fiber Laser and Chirped Gratings for Optically Controlled Phase-Array Antenna Beamforming
Jianliang Yang, Swee Chuan Tjin and Nam Quoc Ngo
This paper presents two approaches to achieve flexinle photonics true-time-delay system for phased-array antenna beamforming. The first one is yo use a wideband wavelength-tunable fiber ring laser source incorporated with a time-delay network based on chirped fiber Bragg gratings with fixed chirp rates; the other one is to use a multiwavelength fiber ring laser source and a novel chirp rate-tunable chirped filter grating based time-delay line. The chirp rate of the chirped grating is tuned by bending a uniform fiber Bragg grating bonded at a slant onto the lateral surface of a simply supported beam. This two kind of variable true-time delay system can provide five-channel time-delayed signals that can be fed to an antenna array to achieve continuous beam scanning. The proposed true-time-delay units with 5-element phased array steerer are suitable for beamforming at frequencies up to 10 GHz.