Fig. 1. Schematic setup of the actively Q-switched Er³⁺/Dy³⁺-codoped fluoride fiber oscillator diode-pumped at 980 nm. LD, laser diode; L1, collimator; L2, aspheric lens; FM, front mirror; L3, off-axis parabolic reflector; DM, dichroic mirror; RF, radio frequency; RDG, ruled diffraction grating. Inset: simplified energy level diagram with some relevant transitions (ET, energy transfer; MR, multiphonon relaxation).

Fig. 2. (a) Average power, (b) pulse width, (c) pulse energy, and (d) peak power versus repetition rate at different launched pump powers.

Fig. 3. (a) Average power and pulse width, and (b) pulse energy and peak power versus launched pump power at the repetition rate of 100 Hz.

Fig. 4. Pulse train and single pulse waveform (inset) at the repetition rate of 100 Hz at the launched pump power of 24.9 W.

Fig. 5. Optical spectrum at the repetition rate of 100 Hz at the launched pump power of 24.9 W. Inset: zoomed optical spectrum.