High COMD, nitridized InAlGaAs laser facets for high reliability 50W bar operation at 805nm

摘要

The 40-year-old laser diode technology underpins applications such as data storage, industrial lasers and telecommunications but still suffers from reliability and longevity issues in high power applications, most notably in pumping of Nd:YVO_4 and Nd:YAG lasers. Despite thermal advantages allowing expansion matched Au/Sn hard soldering, the main problem for InAlGaAs lasers is facet oxidation, which leads to increased absorption and COMD device failure. This article presents a novel process, which atomically seals the surface and eliminates oxidation by forming stable nitrides on the facet. Pulsed testing of 805nm of Al_(>0.20)InGaAs single mode devices with a protective nitride layer demonstrates stable median 1.3W COMD (30MW/cm~2), after one hour of CW screening at 12.5mW/μm (50W bar power). A 200h burn-in at 12.5mW/μm (50W bar power) resulted in an initial power drop of 1-2% and a linear degradation rate of 0.1%/1000h, compared to an initial power drop of 5-18% and a degradation rate of 46%/1000h for lasers with only AR/HR-coatings. A subsequent 1000h life-test at 22.5mW/μm (90W bar power) demonstrated a degradation rate of only 3%/1000h under stress test conditions due to p-side up mounting, 10℃ higher ambient temperature and 57% higher operating current over typical high power bar operating power levels. The QW temperature was 53℃. No sudden device failures occurred.