Al-free 950-nm BA diode lasers with high efficiency and reliability at 50° C ambient temperature

Abstract

We report device properties and results of lifetime tests for Al-free InGaAs/InGaAsP/InGaP broad-area (BA) laser diodes, emitting at 950 nm. The epitaxial layers were grown by metal organic vapor phase epitaxy (MOVPE). The mounted diode lasers have a high wallplug efficiency around 60%, for a resonator length of 2 mm, and about 50% for 4 mm long devices due to low threshold current densities of jth equals 110 . . . 140 A/cm2, high slope efficiencies of 75% and the typical low series resistance of the Al-free material. The lasers were mounted on copper heatsinks, episide-down as well as episide- up. Lifetime tests were performed with a facet load of 15 mW/micrometers at temperatures between 25 degrees Celsius and 70 degrees Celsius and with a facet load of 20 mW/micrometers at 25 degrees Celsius. All diodes survived 3000 h with degradation rates lower than 6 X 10-5h-1 at 50 degrees Celsius and 1 X 10-4h-1 at 70 degrees Celsius as well as 2000 h with a low degradation rates of 2 X 10-5h-1 at 20 mW/micrometer. As far we know, the results belong to the best ones reported until now for Al-free BA laser diodes.