Fig. 1. Schematic diagram of Tm-doped fiber laser

Fig. 2. Output characteristics of fundamental-frequency mode locking when pump power is 270 mW. (a) Optical spectrum; (b) pulse trains; (c) radio-frequency spectrum; (d) shot-to-shot spectrum

Fig. 3. Output characteristics of multiple solitons when pump power is 290 mW. (a) Optical spectrum; (b) pulse trains; (c) autocorrelation trace; (d) radio-frequency spectrum

Fig. 4. Three-dimensional pulse trains. (a) 350 mW; (b) 410 mW

Fig. 5. Numerical simulation of soliton bunch. (a) Soliton bunch containing 6 pulses; (b) soliton bunch containing 8 pulses

Fig. 6. Special mode-locking state at a pumping power of 500 mW. (a) Optical spectrum; (b) pulse trains; (c) autocorrelation trace; (d) radio-frequency spectrum

Fig. 7. Evolution characteristics of shot-to-shot spectra. (a) Shot-to-shot spectrum at pump power of 500 mW; (b) shot-to-shot spectrum at pump power of 1100 mW

Fig. 8. Impact of pumping power. (a) Optical spectrum at different pump powers; (b) output power and output energy at different pump powers