109 fs, 553 MHz pulses from a polarization-maintaining Yb-doped ring fiber laser with SESAM mode-locking

Femtosecond lasers with high repetition rate promote efficiency and accuracy greatly in the field of micro-processing by taking advantage of the so-called ablation cooling effect. In this letter, we demonstrate a novel high-repetition-rate Yb-doped fiber laser configuration with SESAM mode-locking, in which a short segment of commercially available polarization-maintaining gain fiber is implemented. The laser operates at a fundamental repetition rate of 553 MHz and has a maximum average output power of 242 mW. The shortest output pulse has a transform-limited duration of 109 fs. The repetition rate is expected to be boosted to GHz by reducing the spatial length and the proposed high-repetition-rate femtosecond fiber laser would have great potential in the field of micromachining.