Experimental Observation of the Effect of Laser Standing Wave Pattern on the Catastrophic Optical Mirror Damage Threshold for High-Power Single Mode Laser Diodes

摘要

Increases in the Catastrophic Optical Mirror Damage (COMD) threshold in high power coated semiconductor laser diodes have been theoretically attributed to reducing the optical intensity at the semiconductor/dielectric coating interface [1]. Traditionally, this work has focused on the antireflection (AR) facet as this is assumed to have to withstand the highest optical intensity. However, as the robustness of the AR facet improves, the high reflection (HR) facet can become an issue. The HR facet is usually coated after the AR in the coating process and hence has more opportunity to degrade, leading to a lower intrinsic optical damage threshold. Also, during back-reflection events, where light is reflected back into the laser from an external optical element, the optical power on the back facet can greatly exceed that in the free-running case, leading to the possibility of laser failure due to HR COMD.