Design and fabrication of optical waveguides for high-power density laser diodes for LiDAR applications

LiDAR (light detection and ranging) technology has gained significant importance in various fields, including autonomous vehicles, environmental monitoring, and remote sensing. 905nm pulsed laser diodes are an essential component of a LiDAR system, which performance relies heavily on the laser power level and the characteristics of its emitted light beam. While the fabrication of high-power pulsed laser diodes is already mature, reliably combining a high-power level and a concentration of the laser beam (>90%) within a limited emitting width is an ongoing challenge. Another major concern is the development of facet coatings capable of withstanding the high-power density generated by these lasers. Facet degradation due to the excessive optical power leads to a reduced laser efficiency and a risk of increased failure rates Here, we have devised novel optical waveguide designs for triple junction 905nm lasers with optimized mode profiles and an effective confinement structure. This enables lasers to have a power density that is four (4) times higher than the traditional ones and, to confine most of the beam energy within an emitting width of less than 60 µm. Furthermore, our research explores innovative approaches to facet coatings that enhance facet durability and minimize power-induced degradation. This results in exceptionally reliable lasers, as demonstrated by a thousand hours of life test data. Through this work, we have achieved significant advancements in design and fabrication of high-power laser diodes for LiDAR applications. Experimental results demonstrate improved power efficiency, reliable facet coatings, and effective energy confinement within the desired emitting width.