Recent progress in dispersion-based photonic beamforming

The use of dispersion-based techniques for beamforming applications has shown much potential. Investigations are now proceeding to address some of the more practical issues aimed at making the technique viable for "real-world" systems. These issues include the temperature stability and time-delay resolution of the beamformer. The use of chirped fiber gratings alleviates many of the issues with fiber-based dispersion techniques. Another critical issue is the performance and control of the tunable laser source. It was shown that by periodically monitoring a few wavelengths, that the aging characteristics of all laser wavelengths may be compensated simultaneously. Other issues which were not discussed but will be presented include the phase and amplitude stability of the fiber-optic remoting cable, component wavelength flatness, RIN issues and modulator bias stability. Recent demonstrations of a fiber-grating receive beamformer and a simplified, reconfigurable array architecture indicate that many of the practical issues are being addressed.