Technological Approaches Addressing Reliable Output Power Limits in High Power Edge-Emitting Lasers

Abstract

High-power edge-emitting lasers are essential in numerous applications due to their energy-efficient lasing and compact size. However, their reliable output power is often limited by catastrophic optical mirror damage (COMD), primarily caused by self-heating and elevated facet temperatures. Despite advancements in material growth, facet passivation, epitaxial design, and packaging, reliability remains a significant issue. This study introduces two innovative waveguide designs to mitigate self-heating and enhance reliable output power: a 2-section waveguide and a distributed waveguide (DWG). Both designs separate the heat-generating lasing region from the output facet by incorporating a passive section that is electrically isolated but optically connected to the laser section. The 2-section design places a long passive section near the facet, significantly reducing its temperature, while the DWG design employs periodic lasing and passive sections to enhance heat dissipation along an extended cavity length. Experimental results show that both designs effectively lower facet temperatures below the laser body temperature, enabling higher power operation. The 2-section lasers achieve COMD-free operation under high power, thereby improving reliability. These results demonstrate that advanced waveguide structures can significantly enhance the reliability of the laser output facet and pave the way for semiconductor lasers with significantly increased lifetime.