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~\mu $
m, were demonstrated by implementing etched facets. Operating without mirror coating or packaging, the LD with a cavity length of
$500~\mu $
m and a ridge width of
$10~\mu $
m exhibited a threshold current (I
$_{\mathrm {th}}$
) 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~\mu $
m, the lowest Ith of 160 mA was obtained. Our results demonstrated the potential of optimizing SE and Ith 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.