InGaN semiconductor laser diodes for the visible spectral range: design and process optimization of single emitters and bars for applications from mW to kW output power

InGaN lasers in the blue and green wavelength range have opened a wide variety of applications in the past years, which all require unique properties of the employed laser chips. In this paper we will show design and process developments for various InGaN laser designs, each optimized for its specific application. For applications which are very sensitive to energy consumption, like mobile AR/VR devices, we investigated InGaN laser chips with resonator lengths as short as 50 μm. To achieve this, we developed an etched facets technology to overcome the challenges of scribing and breaking for facet generation for such short resonator lengths. The etched facets of these devices are coated on-wafer with a dielectric mirror to achieve the desired reflectivity. Depending on the reflectivity chosen, these devices show ultra-low threshold currents below 3mA and output powers above 50 mW. Combined with a flip-chip design with both contacts on one side, such chips can be integrated into silicon wafer-based beam combiners to generate RBG PIC chips for VR/AR laser projection. For high power applications, we will present data of laser bars. Bars emitting at 430 nm achieved 100 W of continuouswave output power per bar and conversion efficiencies of 50%. Together with bars emitting at 450 nm, that were shown in previous publications, wavelength-multiplexing for materials-processing systems can be realized yielding blue laser light sources with multiple kilowatts of output powers.