[1] Shi Wei, Fu Shijie, Fang Qiang, et al. Single-frequency fiber laser based on rare-earth-doped silica fiber [J]. Infrared and Laser Engineering, 2016, 45(10): 1003001. (in Chinese) doi:  10.3788/IRLA201645.1003001
[2] Simakov N, Hemming A V, Carter A, et al. Design and experimental demonstration of a large pedestal thulium-doped fibre [J]. Optics Express, 2015, 23(3): 3126-3133. doi:  10.1364/OE.23.003126
[3] Wang W C, Zhou B, Xu S H, et al. Recent advances in soft optical glass fiber and fiber lasers [J]. Progress in Materials Science, 2019, 101: 90-171. doi:  10.1016/j.pmatsci.2018.11.003
[4] Eckerle M, Kieleck C, Świderski J, et al. Actively Q-switched and mode-locked Tm3+-doped silicate 2 μm fiber laser for supercontinuum generation in fluoride fiber [J]. Optics Letters, 2012, 37(4): 512-514. doi:  10.1364/OL.37.000512
[5] Zhang Z, Boyland A J, Sahu J K, et al. High-power single-frequency thulium-doped fiber DBR laser at 1943 nm [J]. IEEE Photonics Technology Letters, 2011, 23(7): 417-419. doi:  10.1109/LPT.2011.2106491
[6] Burns M D, Shardlow P C, Barua P, et al. 47 W continuous-wave 1726 nm thulium fiber laser core-pumped by an erbium fiber laser [J]. Optics Letters, 2019, 44(21): 5230-5233. doi:  10.1364/OL.44.005230
[7] Fu S, Shi W, Feng Y, et al. Review of recent progress on single-frequency fiber lasers [Invited] [J]. Journal of the Optical Society of America B, 2017, 34(3): A49-A62. doi:  10.1364/JOSAB.34.000A49
[8] Gebavi H, Milanese D, Balda R, et al. Spectroscopy of thulium and holmium heavily doped tellurite glasses [J]. Journal of Luminescence, 2012, 132(2): 270-276. doi:  10.1016/j.jlumin.2011.08.042
[9] Jackson S D, King T A. Theoretical modeling of Tm-doped silica fiber lasers [J]. Journal of Lightwave Technology, 1999, 17(5): 948-956. doi:  10.1109/50.762916
[10] Li M, Bai G, Guo Y, et al. Investigation on Tm3+-doped silicate glass for 1.8 μm emission [J]. Journal of Luminescence, 2012, 132(7): 1830-1835. doi:  10.1016/j.jlumin.2012.02.022
[11] Tang G, Zhu T, Liu W, et al. Tm3+ doped lead silicate glass single mode fibers for 2 μm laser applications [J]. Optical Materials Express, 2016, 6(6): 2147-2157. doi:  10.1364/OME.6.002147
[12] Zhang L, Zhang J, Yu C, et al. A method for emission cross section determination of Tm3+ at 2.0 μm emission [J]. Journal of Applied Physics, 2010, 108(10): 103117. doi:  10.1063/1.3514147
[13] Tang Guowu, Wen Xin, Huang Kaimin, et al. Tm3+ -doped barium gallo-germanate glass single-mode fiber with high gain per unit length for ultracompact 1.95 µm laser [J]. Applied Physics Express, 2018, 11(3): 032701. doi:  10.7567/APEX.11.032701