Tunable monolithic mode-locked lasers on InP with low timing jitter

Pulse trains with only 2 ps in width and low root-mean-square timing jitter of 220 fs are demonstrated from fine tunable monolithic 40-GHz laser integrated circuits on GaInAsPInP. The repetition rate is tunable within 500 MHz by changing only the gain current and the absorber voltage. Simultaneously, the small pulsewidths are kept constant and the timing jitter remains below 300 fs. The determined time-bandwidth products between 0.37 and 0.5 are close to the transform limit and the fiber coupled optical power is >1 mW. The fact that pulsewidth and timing jitter remain small over the whole repetition-rate tuning range constitutes an important step toward economic commercial applications, especially if frequency shifts caused by fabrication tolerances have to be compensated.