3D and flash lidars are some of the effective technologies expected to speed up lidar commercialisation for AVs. A VCSEL (vertical-cavity surface-emitting laser) emits a high power optical beam vertically from its top surface. It can measure distance and velocity in 3D space and can eliminate the moving parts in the lidar, reducing system cost. Discrete VCSELs have limited output power, but can be scaled in arrays with tens to thousands of VCSELs on one chip, enabling high power devices. They can also provide very short pulses at high power density, and are well suited for automotive applications. Apart from illumination, distance & velocity measurement, VCSELs can identify objects at high speed and under difficult imaging conditions.
A single-mode VCSEL is said to work better than multi-mode in terms of coherent power, spectral purity, and divergence. VCSELs also differ with respect to type of material- gallium nitride (GaN), indium phosphide (InP) and gallium arsenide (GaAs). InP based VCSELs have evolved rapidly because of their highly compatible wavelengths and high-speed communication applications; their operating wavelength range is 1300 to 1550 nm. They’re expensive, though.
The advent of flash lidar is the major enabler for VCSEL technology in automotive industry. Trilumina are a major provider of VCSELs for automotive lidar, and are collaborating with semiconductor giant Analog Devices in an effort to produce a new integrated, solid-state illuminator modules for automotive flash lidars. Other major VCSEL suppliers include Finisar, Broadcom, Lumentum, II-VI, Thor Labs, AMS, Osram, Hamamatsu, Princeton Optronics, Vixar (acquired by Osram), Philips Photonics, Avago Technologies, IQE, Lasertel, and others.
