Wavelength Stabilized 905 nm Diode Lasers in the 100 W Class for Automotive LiDAR

Diode lasers generating optical pulses with high peak powers and pulse lengths in the nanosecond range are key components of systems for free-space communication, metrology, material processing, spectroscopy, and light detection and ranging (LiDAR) as needed for object detection and autonomous driving. For the automotive application a number of special requirements have to be fulfilled additionally to a high output power: Due to eye safety reasons favored pulse powers of ~100 W can only be used within a pulse length of 2 ns; to avoid absorption by water vapor the emission wavelengths have to be shorter than 920 nm; uncooled operation demands laser operation over a wide temperature range from -40°C to +85°C; for the suppression of the sun light and a high signal to noise ratio optical band filters are necessary. The last requirement can be met by the integration of a distributed Bragg reflector (DBR) into a part of the cavity [1]. In a first step the epitaxial layer structure including the active region has been optimized (a) in order to lock the lasing wavelength to the Bragg wavelength over the whole temperature range and (b) to avoid carrier accumulation outside of the active region [2]. Tailored high-speed electrical units are used for the generation of the current pulses.