Fig. 1. Experimental setup of the tunable Q-switched Er³⁺/Dy³⁺ codoped ZrF₄ fiber laser using the Fe²⁺:ZnSe crystal or InAs SA. LD, laser diode; L1 and L2, aspheric lenses; L3, off-axis parabolic reflector; FM, front mirror; DM, dichroic mirror; L4 and L5, CaF₂ plano-convex lenses; LF, longpass filter; BT, beam trap.

Fig. 2. Fe²⁺:ZnSe crystal based laser output characteristics at a fixed wavelength. (a) Temporal behaviors; (b) optical and RF (inset) spectra; (c) pulse width and repetition rate versus pump power; (d) average power and pulse energy versus pump power.

Fig. 3. Fe²⁺:ZnSe crystal-based laser output characteristics with the tuned wavelength. (a) Optical spectra; (b) pulse width and repetition rate versus wavelength; (c) average power and pulse energy versus wavelength.

Fig. 4. InAs SA-based laser output characteristics with the tuned wavelength. (a) Optical spectra; (b) pulse width and repetition rate versus wavelength; (c) average power and pulse energy versus wavelength.