Analysis of degradation mechanisms in high power AlGaAs 808 nm laser bars

In this work we study the degradation mechanisms of 20 W CW AlGaAs linear array bars by analyzing the subthreshold Optical Power-Current-Voltage characteristics (P-I-V) at different aging times. The laser structure is a single quantum well graded index separate confinement heterostructure (SQW-GRINSCH) grown by metal organic chemical vapor deposition. Monolithic 1 cm linear array bars with multiple emitters were mounted p-side down onto high thermal conductivity submounts. Seven different laser bars coming from the same wafer were aged at a constant current of 30 A. The main optoelectronic characteristics (threshold current, slope efficiency, conversion efficiency, lasing wavelength) and the subthreshold P-I-V characteristics were measured as a function of the aging time. The spontaneous optical power emitted from the low-reflectivity facet and the external voltage were accurately measured at drive currents ranging between 1 nA and 1 A