Sub-Femtosecond Timing Jitter From a SESAM Mode-Locked Yb-Fiber Laser

We demonstrate sub-femtosecond timing jitter of ultrashort pulses from a dispersion managed Yb-fiber laser mode-locked by a SESAM. Timing jitters of the mode-locked Yb-laser under different dispersion conditions (when the intra-cavity dispersions are −0.005 ps², +0.001 ps², +0.006 ps²) are characterized by the single-crystal balanced optical cross-correlator. In our experiment, an ultra-low timing jitter of 48 attoseconds is achieved when the jitter spectral density is integrated from 3 kHz to 1 MHz offset frequency. We think that the obtained timing jitter level is the lowest for fiber lasers mode-locked by real saturable absorbers. This ultra-low timing-jitter, stably mode-locked fiber laser source is expected to be used for high precision applications outside of the laboratory.