High power passively Q-switched Er3+-doped ZBLAN fiber laser at 2.8 µm based on a semiconductor saturable absorber mirror

We report a 976 nm diode-pump passively Q-switched Er3+-doped ZBLAN fiber laser based on a semiconductor saturable absorber mirror (SESAM). The maximum average output power of 3.01 W was obtained at a slope efficient of 17%. Stable passively Q-switched pulses with a pulse energy of 10.82 µJ and a pulse duration of 0.45 µs, corresponding to a peak power of 24.45 W, were obtained at a repetition rate of 278.5 kHz and a center wavelength of 2798.8 nm. To the best of our knowledge, this is the highest current average output power from a passively Q-switched fiber laser at 2.8 µm based on a SESAM.