Degradation mechanisms of heterogeneous III-V/Silicon loop-mirror laser diodes for photonic integrated circuits

This paper reports on the degradation processes of heterogeneous III-V/Silicon loop-mirrors laser-diodes designed as the optical sources for next-generation Photonic Integrated Circuits (PICs) operating at 1.55 mu m. By submitting the devices to a series of constant-current accelerated aging experiments we were able to identify a common set of degradation mechanisms, including: (i) an increase in threshold current, (ii) a decrease of the subthreshold emission, (iii) a decrease in the operating voltage of the device and (iv) a small decrease in the slope efficiency of the laser. The strong correlation between these degradation processes suggests that the loss in optical performance experienced by the devices can be attributed to a decrease in the non-radiative carrier lifetime, as a consequence of the generation/propagation of defects towards the active region of the laser diodes.