Tm-Ho co-doped fiber-based high repetition rate passive Q-switching of an Er-doped fiber laser

An all-fiber Q-switched Er-doped laser is built with a ring cavity. Stable Q-switching is demonstrated with a Tm-Ho co-doped fiber saturable absorber. The maximum repetition rate of the laser system reaches 42 kHz, which is much larger than that with Tm singly doped fiber saturable absorbers. Analysis shows that interaction between thulium and holmium ions is the main reason for this high repetition rate operation.