Effects of having two populations of defects growing in the cavity of a semiconductor laser

In this study, we show the effects of the growth of two noninteracting populations of defects in the cavity of a semiconductor laser diode, induced by accelerated lifetesting. The development of one type of defect is considered to give rise to a particular failure mode or mechanism. Using a multicomponent model, we demonstrate that the evolution of the threshold current as a function of time is strongly affected by the operating temperature. We describe the progression of the degradation in terms of different thermal activation energies associated with each of the different failure modes. This observation explains why a common shape of the aging curve is seldom observed from one experiment to another and why it is difficult to have one universal threshold-aging model that everyone agrees on. In addition, the study offers insight on the estimation of the lifetime of a semiconductor laser diode.