Recently, Associate Professor Hongyan FU from Tsinghua-Berkeley Shenzhen Institute (TBSI) was invited by the international journal Nature to publish a critical analysis and review of on-chip LiDAR imaging systems. The paper summarizes and discusses the key technologies currently used in on-chip LiDAR systems, and specifically addresses the on-chip integrated focal plane switching array technology. The performance of the system is also analyzed in the context of the important demands of future consumer electronics and smart cities for the LIDAR systems, and future directions for the development of this technology area are proposed.
Figure | Architecture and working principle of focal plane switching arrays, (Source: Nature (2022): 232-233)
The article focuses on two current integrated beam-steering devices for on-chip LIDAR: the optical phased array (OPA) and the focal plane switching array (FPSA). The working mechanism of OPA is analyzed and the article identifies the reasons that make them difficult to integrate densely on a single chip on a large scale. In contrast, FPSA uses a camera-like optical system to map each angle in the field of view where the target is located to each pixel in the focal plane behind the imaging lens. The article suggests the possibility of integrating a large array of antennas on a single chip. The article further reviews the work of Ming C. WU's group at the University of California, Berkeley, USA, published in the same issue of Nature on a MEMS-based large-scale FPSA LiDAR system. The article presents the problem of insufficient lateral resolution in FPSA-based LIDAR systems and offers a solution to improve the performance by reducing the size of the optical switches. Finally, the article comments that further miniaturization and improvements in performance will make FPSA a promising technology for applications including megapixel 3D lidar and optical communications with the mature of processing technologies.
Link to full article:
Written by Zhi Li & Hongyan Fu
Edited by Alena Shish & Yuan Yang & Manyuan Li