Opt Express. 2023 Feb 13;31(4):6514-6528. doi: 10.1364/OE.477952.
Light detection and ranging (lidar) is widely accepted as an indispensable sensor for autonomous vehicles. There are two fundamental challenges in a lidar system: optical beam steering technique and ranging method. Optical phased array (OPA) is considered as one of the most promising beam steering schemes due to its solid state, compact size, and high reliability. As for ranging method, time-of-flight and frequency-modulate continuous-wave (FMCW) are commonly utilized in numerous research. However, they are impractical to commercial OPA lidar due to either requiring excessive optical power or the poor stability, high complexity, and high insertion loss of the FMCW source. As a result, the development of OPA lidars is significantly hindered by the lack of a feasible ranging method. In this paper, we present a phase-modulated continuous-wave (PhMCW) ranging method with excellent ranging accuracy and precision. Ranging error as low as 0.1 cm and precision on the order of 3.5 cm are achieved. In addition, theoretical and experimental study on simultaneous velocity measurement is carried out and velocity error as low as 0.15 cm/s is obtained. Finally, we develop a proof-of-concept OPA-PhMCW lidar and obtain a point cloud with excellent fidelity. Our work paves a novel approach to solid-state, cost-effective and high-performance OPA lidars.
激光雷达（lidar）被广泛认为是自动驾驶汽车不可或缺的传感器。激光雷达系统有两个基本挑战：光束转向技术和测距方法。由于其固态、紧凑尺寸和高可靠性，光学相控阵（OPA）被认为是最有前途的光束转向方案之一。至于测距方法，飞行时间和调频连续波（FMCW）在许多研究中都得到了广泛应用。然而，由于需要过多的光功率或 FMCW 源的稳定性差、复杂性高、插入损耗大，它们在商业 OPA 激光雷达中并不实用。因此，缺乏可行的测距方法极大地阻碍了 OPA 激光雷达的发展。在本文中，我们提出了一种具有出色测距精度和精度的相位调制连续波（PhMCW）测距方法。实现了低至 0.1 cm 的测距误差和 3.5 cm 量级的精度。此外，还进行了同时进行速度测量的理论和实验研究，得到了低至 0.15 cm/s 的速度误差。最后，我们开发了一个概念验证的 OPA-PhMCW 激光雷达，并获得了具有出色保真度的点云。我们的工作为固态、经济高效和高性能的 OPA 激光雷达开辟了一条新途径。
