[1] [1] Liu K, Liu J, Shi H X, et al. High power mid-infrared supercontinuum generation in a single-mode ZBLAN fiber with up to 21.8 W average output power [J]. Optics Express, 2014, 22(20): 24384-24391.

[2] [2] Jackson S D, King T A. Theoretical modeling of Tm-doped silica fiber lasers [J]. Journal of Lightwave Technology, 1999, 17(5): 948-956.

[3] [3] Hanna D C, Percival R M, Smart R G, et al. Efficient and tunable operation of a Tm-doped fibre laser [J]. Optics Communications, 1990, 75(3/4): 283-286.

[4] [4] Lin L. Research on Double-clad Tm3+-doped Fiber Laser Pumped by 793 nm LD [D]. Changchun: Changchun University of Science and Technology, 2014.

[5] [5] Jin X X. Research on Tandem Pumping Technique for Fiber Lasers at 2 μm [D]. Changsha: National University of Defense Technology, 2018.

[6] [6] Li N. Study on Widely Tunable Ultrashort Pulse Fiber Laser Around 2 μm and Its Application [D]. Changchun: Jilin University, 2017.

[7] [7] Xu J. Research on Optimization of 793 nm Laser Pumped Thulium Doped Fiber Amplifier [D]. Changchun: Changchun University of Science and Technology, 2018.

[8] [8] Kouznetsov D, Moloney J V. Efficiency of pump absorption in double-clad fiber amplifiers III. Calculation of modes [J]. Journal of the Optical Society of America B, 2002, 19(6): 1304-1309.

[9] [9] Dong Z K, Song Y R. Research progress of mode-locked fiber lasers based on saturable absorbers [J]. Chinese Journal of Lasers, 2021, 48(5): 0501006.

[10] [10] Lu X L. The Experimental Study on the Nonlinear Polarization Rotation Lock Mode Laser [D]. Beijing: Beijing University of Posts and Telecommunications, 2018.