A Low Repetition Rate All-Active Monolithic Passively Mode-Locked Quantum-Dot Laser

A passively mode-locked laser with a 2.1-GHz fundamental repetition rate is demonstrated using a 20-mm-long monolithic two-section quantum-dot laser. A pulsewidth as short as 15.4 ps was measured using a high-speed sampling scope. The product of the peak power and average power in this laser is treated theoretically and shown experimentally to nearly double by roughly quadrupling the cavity length.