We report a multi-beam single-photon light detection and ranging (LiDAR) in eye-safe band at 1.5 µm with hybrid multiplexing in wavelength and time. 16 independent laser diodes with equal frequency spacing in dense wavelength division multiplexing (DWDM) were combined with a blazed grating to generate multi-beam dispersing with equal angle in space as the LiDAR laser source. Meanwhile, time division multiplexing (TDM) was applied on the 16 laser diodes as well. A single-pixel single-photon detector (SP-SPD) was used to detect the echo photon signal of all laser beams by TDM. In this way, we constituted a compact optical system without multi-beam transceiver alignment. The LiDAR system was simple and robust with this hybrid multiplexing technology. An outdoor photon-counting imaging within 75-m range was achieved, with the laser power lower than 1/10 of the human eye safety threshold. It has high application potential in the field of automatic driving with strict eye safety requirements.

我们报告了 1.5 µm 人眼安全波段的多光束单光子光探测和测距 (LiDAR)，波长和时间混合复用。密集波分复用 (DWDM) 中具有相同频率间隔的 16 个独立激光二极管与闪耀光栅相结合，以产生与 LiDAR 激光源相同的空间角度分散的多光束。同时，时分复用 (TDM) 也应用于 16 个激光二极管。使用单像素单光子探测器（SP-SPD）通过 TDM 检测所有激光束的回波光子信号。这样，我们就构成了一个没有多光束收发器对准的紧凑型光学系统。采用这种混合多路复用技术的 LiDAR 系统既简单又可靠。实现了 75 米范围内的室外光子计数成像，激光功率低于人眼安全阈值的1/10。在人眼安全要求严格的自动驾驶领域具有很高的应用潜力。