Demonstration of Watt Level 375 nm Short Cavity Laser Diode with Etched Facets

III-Nitride Laser diodes (LDs) emitting in the Ultra-Violet A (UVA) range with various cavity lengths, down to 100 μm, were demonstrated by implementing etched facets. Operating without mirror coating or packaging, the LD with a cavity length of 500 μm and a ridge width of 10 μm exhibited a threshold current (I _th ) of 300 mA and a slope efficiency (SE) exceeding 1W/A under pulse conditions. The highest power of 2.16 W was obtained under an injection current of 3 A. As the cavity length further decreased to 100 μm, the lowest I _th of 160 mA was obtained. Our results demonstrated the potential of optimizing SE and I _th for LDs in the UV A range with a careful design of the cavity lengths, especially toward the short cavities side, facilitated by etched facets. Such optimization can be particularly useful for applications prioritizing low power dissipation such as photonic integrated circuits.