Stability and Spectral Behavior of Grating-Controlled Actively Mode-Locked Lasers

Amplitude, timing, and wavelength instabilities in a semiconductor mode-locked laser are studied experimentally and by using an accurate numerical model. It is shown that these instabilities can occur when the RF drive frequency is tuned to give a minimum average pulsewidth. We show that experimental measurement techniques, such as sampling and averaging, can mask these instabilities. Using our numerical model, we show that the wavelength instability is associated with the amplitude and timing instabilities and that the large broadening of the optical spectrum observed experimentally is caused by a cyclic wavelength instability.