Relation between Degradation Rate and Photocurrent in GaAs/AlGaAs DH Lasers

Zn-diffused planar stripe GaAs/AlGaAs DH lasers without coatings were tested at 50 C. The laser output power was automatically controlled to 3 mW/facet, and the test continued until the driving current exceeded 250 mA. The mirror surface showed no signs of deformation or oxidation when observed with an optical microscope. It is found that degradation near the surface is due to increased loss in photon absorption and carrier injection, attributed to nonradiative recombination. The suggested testing technique based on initial photocurrent measurements can help select lasers with a long service life.