Performance and reliability of high-intensity AlGaAs laser arrays

Abstract

Changing the layer structure of the AlGaAs LD bars, the dependence of degradation on conversion efficiency and internal loss is examined in this paper. Using four kinds of LD bars mounted on the water-coolers, we measured output and aging characteristics. The internal loss estimated from the free carrier absorption has a close relationship with the degradation of the AlGaAs LD bars. On the other hand, in the region we examined, the conversion efficiency is not the dominant factor in determining the degradation. The free carrier absorption locally raises the lattice temperature and accelerates the propagation of defects in the lattice. On the other hand, the thermal power caused by the injection current uniformly raises the LD temperature and affects the local lattice in minimal manner. Therefore, the degradation dominantly depends on the internal loss.