Broadband Frequency-Hopping Radar With Fourier Domain Mode-Locking Period-One Laser Dynamics

A frequency hopping (FH) radar based on period-one oscillation laser dynamics with Fourier domain mode-locking (FDML) is proposed and experimentally demonstrated. In the transmitter, a broadband FH signal is generated by adjusting injection strength through intensity modulation. By further incorporating an optoelectronic feedback loop with the temporal period of the FH signal matched with its round-trip delay, the frequency stability and accuracy are greatly improved. In the receiver, to reduce the sampling rate and computational complexity, self-referenced frequency down conversion is applied and a kernel function correlation algorithm is adopted in digital signal processing to procure the high-resolution range profile. In the experiment, an FH signal with a bandwidth of 8 GHz is generated, based on which the detections of single-target and two-targets are demonstrated respectively, achieving a range resolution of 2.15 cm. The proposed photonics-based FH radar with FDML-based P1 dynamics for signal generation is supposed to find more applications in further high-resolution radar detection and imaging.