Fig. 1. Schematic of the all-fiber wavelength-tunable passively mode-locked thulium-doped fiber laser

Fig. 2. Variation curve of the laser output wavelength with the temperature of high-birefringence fiber

Fig. 3. Output spectrs of the all-fiber wavelength-tunable passively mode-locked thulium-doped fiber laser

Fig. 4. Average output power of the mode-locked laser at different central wavelengths

Fig. 5. Output laser pulse train

Fig. 6. Autocorrelation trace of the passively mode-locked thulium-doped fiber laser