Mitigation of RF power degradation in dispersion-based photonic true time delay systems

Photonic true time delay (TTD) systems based on optical dispersive devices suffer from RF power degradation induced by dispersion. When the dispersion value is 100 ps/nm, the -3 dB bandwidth are limited to 17.6 GHz and 4.4 GHz for systems using lasers and broadband light sources, respectively. A multichannel chirped fiber grating is used to mitigate the RF power degradation in a dispersion-based TTD link for the first time. Both the experimental and theoretical results show that the degradation can be completely eliminated by using this method.