Fig. 1. Schematic of the nanosecond Tm-doped all-fiber dual-cavity laser

Fig. 2. Pulse trains at different repetition rates under program 1. (a) Repetition rate of 63 kHz; (b) repetition rate of 80 kHz

Fig. 3. Optical spectrum of the Tm-doped all-fiber dual-cavity laser under program 1

Fig. 4. Pulse trains at different repetition rates under program 2. (a) Repetition rate of 20.0 kHz; (b) repetition rate of 33.3 kHz

Fig. 5. Optical spectra of the nanosecond Tm-doped all-fiber dual-cavity laser under program 2. (a) Output at 1904 nm and 1993 nm; (b) output at 1993 nm

Fig. 6. Relationship between average output power and pump power under different experimental programs. (a) Program 1; (b) program 2

Fig. 7. Relationship between repetition rate or pulse width and pump power under different experimental programs. (a) Program 1; (b) program 2

Fig. 8. Relationship between pulse energy or peak power and pump power under program 2

Fig. 9. Single pulse under different experimental programs. (a) Program 1; (b) program 2