Highly reliable, high brightness, 915nm laser diodes for fiber laser applications

High brightness, high power, and highly reliable 915nm InAlGaAs laser diodes with optimized design are reported in this paper. The laser diodes exhibit excellent performance, such as, high slope efficiency, low threshold current, low voltage, etc., which make them suitable for high brightness operation. The aging test data shows no failures during aging test and more than 220,000 hours estimated lifetime for 90um emitter laser diodes at 8W CW operation. The aging test with the same emitter size at higher stress conditions showed sudden failure that corresponds to catastrophic optical damage (COD) on the facet. A novel large optical cavity (LOC) epi-structure with flat-top near field intensity distribution was developed. The maximum output power is up to 23W under CW testing condition at 25 degrees C, which is highest level achieved so far. The output power is limited by thermal roll over and there is no COD occurring. This data shows Axcel's technologies can further increase the brightness to over 110mW per micron for 915nm laser diodes. This type of laser diodes is essential for pumping fiber lasers to replace CO2 lasers for industry applications.