Considerations on the Degradation of DFB Lasers

Abstract

Reliability of recently developed 1.3 µm and 1.55 µm high power DFB lasers is investigated from the viewpoint of wear-out failure and random failure modes. The change in spectral characteristics during operation and the electric surge endurance level is also presented.

The failure modes are similar to those of FP lasers. The degradation speed mainly depends on the injected current density and is affected by BH interface degradation. The median lifetime at 50°C is estimated to be greater than 10⁵ hours for laser output powers of around 15 mW for 1.3 µm lasers and around 10 mW for 1.55 µm lasers. The random failure rate is also estimated to be less than 200 FITs. In addition, there is no difference between the endurance level against electric surge of DFB and FP lasers and of lasing wavelengths of 1.3 µm and 1.55 µm. These results show that DFB lasers could operate at laser output powers of 10 mW even in practical optical transmission systems.