Remote Radar Based on Chaos Generation and Radio Over Fiber

An ultrawideband (UWB) radar system for remote ranging based on microwave-photonic chaotic signal generation and fiber-optic distribution is proposed and demonstrated experimentally. In this system, an optical-feedback semiconductor laser with optical injection in the central office generates photonic UWB chaos as probing signal, and two single-mode fibers transport the optical signal to the remote antenna monitoring terminal and return the corresponding echoed signal back to the central office. In the remote antenna terminal, the photonic signal is transformed into microwave chaos by a fast photodetector and then launched to target by a transmitting antenna, and the echoed signal received by another antenna is converted into optical domain by modulating a laser diode. The target ranging is achieved at the central office by correlating the echoed signal with the reference signal. We experimentally realize a detection range of 8 m, for a free-space target, after 24-km remote distance, and achieve a ranging resolution of 3 cm for single target and 8 cm for double targets. In another fiber link branch with 15-km fiber transmission, we obtained the 2-cm ranging resolution for a single target.