Abstract
We study the optical gain and alpha factor of InAs/InAlGaAs quantum-dash lasers on InP substrate after being subjected to the postgrowth intermixing process. The intermixing was achieved using dielectric capping process that involves the deposition of dielectric film and subsequent rapid thermal annealing. Compared to the un-intermixed laser, we found that the intermixed lasers with a 93 nm bandgap blue-shift exhibit good material quality with improved differential gain and comparable alpha factor.