All-fiber interferometer-based repetition-rate stabilization of mode-locked lasers to 10 -14 -level frequency instability and 1-fs-level jitter over 1 s.

We report on all-fiber Michelson interferometer-based repetition-rate stabilization of femtosecond mode-locked lasers down to 1.3×10-14 frequency instability and 1.4 fs integrated jitter in a 1 s time scale. The use of a compactly packaged 10 km long single-mode fiber (SMF)-28 fiber link as a timing reference allows the scaling of phase noise at a 10 GHz carrier down to -80  dBc/Hz at 1 Hz Fourier frequency. We also tested a 500 m long low-thermal-sensitivity fiber as a reference and found that, compared to standard SMF-28 fiber, it can mitigate the phase noise divergence by ∼10  dB/dec in the 0.1-1 Hz Fourier frequency range. These results suggest that the use of a longer low-thermal-sensitivity fiber may achieve sub-femtosecond integrated timing jitter with sub-10-14 -level frequency instability in repetition rate by a simple and robust all-fiber-photonic method.