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Since Stanley, the self-driven Stanford car equipped with five SICK LIDAR sensors won the 2005 DARPA Challenge, the race to developing and deploying fully autonomous, self-driving vehicles has come to a full swing. By now, it has engulfed all major automotive companies and suppliers, major trucking and taxi companies, not to mention companies like Google (Waymo), Apple and Tesla. With the notable exception of the Tesla self-driving cars, a LIDAR (Light, Detection and Ranging) unit is a key component of the suit of sensors that allow autonomous vehicles to see and navigate the world. The market space for lidar units is by now downright crowded, with a number of companies and their respective technologies jockeying for long-run leading positions in the field. Major lidar technologies for autonomous driving include mechanical scanning (spinning) lidar, MEMS micro-mirror lidar, optical-phased array lidar, flash lidar, frequencymodulated continuous-wave (FMCW) lidar and others. A major technical specification of any lidar is the operating wavelength. Many existing systems use 905 nm diode lasers, a wavelength compatible with CMOS-technology detectors. But other wavelengths (like 850 nm, 940 nm and 1550 nm) are also investigated and, in the long run, the telecom nearinfrared range (1550 nm) is expected to experience significant growth because it offers a larger detecting distance range (200-300 meters) within eye safety laser power limits while also offering potential better performance in bad weather conditions. This paper discusses the above-mentioned technical (optics and photonics) aspects of the most common lidar technologies, with the educational focus of identifying opportunities for employing such discussions in introducing optics to broader engineering audiences, drawing in part on experiences and examples from Kettering University.
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