Timing Jitter Reduction of a Mode-Locked VECSEL Using an Optically Triggered SESAM

A technique for actively stabilizing the repetition rate of a mode-locked vertical external-cavity surface-emitting laser is presented using an optically triggered semiconductor saturable absorber mirror. This method enables a significant reduction of the timing jitter measured in the frequency range [100 Hz, 10 MHz] and makes this kind of externally locked laser suitable for high-speed sampling of microwave signals. The experimental demonstration shows jitter reduction by a factor of 16 from 8 ps down to 423 fs for a 1.68-GHz repetition rate pulse train. The hold-in locking bandwidth and stabilization efficiency are shown to be a function of the average power and modulation index of the optical control signal.