Photon-Counting Chirped Amplitude Modulation Lidar With 1.5-GHz Gated InGaAs/InP APD

We demonstrated a photon-counting chirped amplitude modulation (CAM) Lidar at 1550 nm. In the previous studies, the CAM bandwidth was limited <30 MHz due to the large dead time of the single-photon detectors. In our CAM Lidar system, an InGaAs/InP avalanche photodiode was operated in 1.5-GHz sine-wave gated Geiger mode to reduce the dead time to 6.4 ns. As a result, the CAM bandwidth exceeded 200 MHz, while the modulation period was 0.5 ms, leading to a direct distance accuracy of 0.12 m in daylight environment. This system presented a potential for high accuracy and eye-safe CAM Lidar system.