Evaluation of the optical-coupling efficiency of InGaAlAs-InGaAsP butt joint using a novel multiple butt-jointed laser

We quantitatively estimated the optical-coupling efficiency at the InGaAlAs-InGaAsP butt-joint (BJ) part by fabricating a novel multiple-butt-jointed (MBJ) laser. The lasing characteristics of InGaAlAs-InGaAsP MBJ lasers formed by in situ cleaning process showed a high optical-coupling efficiency of approximately 98%, which is comparable to that of a conventional InGaAsP-InGaAsP MBJ lasers. Thus, high-quality BJ-based heterointegration of InGaAlAs and InGaAsP was successfully demonstrated.