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 μm. 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 sub-threshold 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.