Passive harmonically mode-locked ytterbium-doped fiber laser

In this paper, we report a passive harmonic mode-locking of an Yb-doped fiber laser operating both in normal an anomalous dispersion regime. The fiber laser setup is a stretched-pulse Yb-doped double-clad fiber ring cavity. The laser output obtained from the zeroth diffraction order of the first grating can be adjusted by rotation of a simple half wave plate. The repetition rate is thus 102 MHz. The supermodes suppression is more than 60 dB. After extra-cavity compression the pulse duration is reduced to about 120 fs. Pulse energy is about 1.7 nJ