THz optical pulses from a coupled-cavity quantum-dot laser

摘要

Optical pulses are generated from a coupled-cavity quantum-dot (QD) laser consisting of a short QD-waveguide Fabry Perot (F P) cavity and three long external fiber Bragg grating (FBG) cavities.When the laser is biased at low operation current, the feedback from the external cavities dominates and laser pulses have a 1.01 THz repetition rate, determined by the equal frequency difference of the three FBGs.We are thus able to decouple the repetition rate of a mode-locked laser from the cavity length.With much higher bias current, the QD F P cavity dominates and the repetition rate is switched to 43.8 GHz, defined by the length of the F P cavity.