Failure Analysis Engineering of Semiconductor Lasers

High-power, diode pump laser modules with improved 0.25% antireflective (AR) coating exhibited low (weak) or zero (dead) power emitters after 1000+ hours life-test. Catastrophic optical mirror damage (COMD) was suspected due to a facet coating upgrade but was not physically observed. Electroluminescence ‘fingerprinting’ lent to a contradictory catastrophic bulk damage (COBD) failure mechanism. The Customer wished to clearly understand how an AR coating change caused COBD and not COMD. This paper emphasizes how the astute failure analyst must remain a ‘conscious observer’ deploying concerted analysis steps to truly unmask root-cause amidst conflicted stakeholders.