Growth Over Grating 1.5microns DFB Lasers

Growth over grating is an important process step in determining the performance of DFB lasers. While destructive methods such as SEM can be used to assess the regrowth step and preservation of the grating, non-destructive means are desirable for process monitoring. In this work, we demonstrate how the grating overgrowth quality can be evaluated by measuring the photolumionescence efficiency (PLE) of the MQW active stack grown on top of these layers.