Stable mode locking via ground- or excited-state transitions in a two-section quantum-dot laser

The authors demonstrate stable mode locking that involves transitions within either the ground state (1260nm) or the excited state (1190nm) in a two-section quantum-dot laser, at repetition frequencies of 21 and 20.5GHz, respectively. The average power of the mode-locked output was in excess of 35mW for operation in the ground state and 25mW in the excited state. The selection of pulse generation between these states in the mode-locking regime is controlled by the electrical biasing conditions.