Colliding-pulse passive harmonic mode-locking in a femtosecond Yb-doped fiber laser with a semiconductor saturable absorber

Abstract

We demonstrate a passive harmonic mode-locked femtosecond Yb-doped fiber laser employing a semiconductor saturable absorber in a colliding-pulse configuration. 380-fs pulses at 605 MHz repetition rate with >60 dB supermode suppression is achieved.