Modal Gain and Photoluminescence Investigation of Two-State Lasing in GaAs-Based 1.3 μm InAs/InGaAs Quantum Dot Lasers

Two-state lasing was investigated on the fabricated high-performance InAs/InGaAs quantum dot (QD) lasers. Both excitation-dependent photoluminescence (PL) measurements and modal gain measurements based on the Hakki Paoli method, for the first time, on the two-state transitions were performed. The two lasing states are attributed to ground state (GS) and excited state (ES) transitions. The significant carrier recombination competition has been observed at the GS and ES transitions from both PL and modal gain analyses. Unlike that in the quantum well lasers, the gain was not pinned at the GS state after GS lasing in QD lasers. (C) 2013 The Japan Society of Applied Physics