Fig. 1. Configuration of single longitudinal mode Tm-doped fiber laser

Fig. 2. (a) Output spectrum of active fiber ring cavity; (b) reflection spectrum of uniform FBG (red dashed line) and transmission spectrum of F-P filter (solid blue line)

Fig. 3. Reflectivity spectrum of FBG (red dashed line) and transmission spectrum of F-P filter (blue solid line)

Fig. 4. (a) Reflection spectrum of saturated absorber; (b) influences of saturated absorber length on bandwidth and central reflectivity

Fig. 5. Schematic of single longitudinal mode selection principle of the laser

Fig. 6. (a) Typical output spectrum of laser; (b) output spectra of 10-times repeated scans with 10 min intervals

Fig. 7. Fluctuations of laser center wavelength and output power

Fig. 8. Variation of output power of laser with pumping power

Fig. 9. Frequency spectra of proposed laser. (a) With saturable absorber; (b) without saturable absorber

Fig. 10. Frequency noise spectrum of laser