Static and dynamic measurements of the α-factor of five-quantum-dot-layer single-mode lasers emitting at 1.3 μm on GaAs

The “material” and “device” linewidth enhancement factor α of five-quantum-dot (QD)-layer single-mode lasers emitting at 1.3 μm are investigated using two methods. The Hakki–Paoli method associated with pulsed analysis of Fabry–Perot modes below threshold demonstrates a record value of 0.7 at 1295 nm. High-frequency current modulation experiments showed a value of 2.0 just above threshold at 1.3 μm with a steady increase with the current. Dynamic measurements on a three-QD layer device, with a reduced ground state optical gain, showed a similar increase of α with current but at a higher rate.