An experimental and numerical study of Q-switched mode-locking in monolithic semiconductor diode lasers

We present experimental results of Q-switched mode-locking (QML) of a monolithic two-section semiconductor laser. We demonstrate tuning of the Q-switched envelope repetition rate with pumping current over the range of 0.4 to 1.6 GHz. Detailed numerical modeling is used to study a range of similar devices and to investigate the mechanisms and conditions for QML to occur. We also discuss design conditions for increasing the tuning up to 4 GHz.