[1] Meng J, Zhang W, Zhao K Q et al. Performance of a homemade thulium-doped fiber laser oscillator[J]. Chinese Optics, 12, 1109-1117(2019).

[2] Scholle K, Lamrini S, Koopmann P et al. 2 µm laser sources and their possible applications[M]. Frontiers in guided wave optics and optoelectronics(2010).

[3] Zhao G J, Wang Y L, Chen B et al. LD side-pumped passively Q-switched ring cavity single longitudinal-mode laser[J]. Acta Optica Sinica, 42, 1914003(2022).

[4] Liu S. Research on high-quality multi-wavelength and pulsed laser seed source for 2 μm band high-power fiber laser system[D], 20-28(2017).

[5] Omiya T, Yoshida M, Nakazawa M. 400 Gbit/s 256 QAM-OFDM transmission over 720 km with a 14 bit/s/Hz spectral efficiency using high-resolution FDE[J]. Optics Express, 21, 2632-2641(2013).

[6] Liu Y, Liu J Q, Chen WB. Eye-safe, single-frequency pulsed all-fiber laser for Doppler wind lidar[J]. Chinese Optics Letters, 9, 090604(2011).

[7] Liu B, Jia C L, Zhang H et al. DBR fiber laser-based active temperature sensor and its applications in measurement of fiber birefringence[J]. Microwave and Optical Technology Letters, 52, 41-44(2010).

[8] Geng J H, Spiegelberg C, Jiang S B. Narrow linewidth fiber laser for 100-km optical frequency domain reflectometry[J]. IEEE Photonics Technology Letters, 17, 1827-1829(2005).

[9] Guo Z C, Xie F, Guo X L et al. Multiwavelength and narrowlinewidth fiber laser based on composite resonator[J]. Laser & Optoelectronics Progress, 59, 1714008(2022).

[10] Katori H. Optical lattice clocks and quantum metrology[J]. Nature Photonics, 5, 203-210(2011).

[11] Chou C W, Hume D B, Rosenband T et al. Optical clocks and relativity[J]. Science, 329, 1630-1633(2010).

[12] Chen D, Fu H, Liu W. Single-longitudinal-mode erbium-doped fiber laser based on a fiber Bragg grating Fabry-Perot filter[J]. Laser Physics, 17, 1246-1248(2007).

[13] Cheng Y, Kringlebotn J T, Loh W H et al. Stable single-frequency traveling-wave fiber loop laser with integral saturable-absorber-based tracking narrow-band filter[J]. Optics Letters, 20, 875-877(1995).

[14] Meng Z, Stewart G, Whitenett G. Stable single-mode operation of a narrow-linewidth, linearly polarized, erbium fiber ring laser using a saturable absorber[J]. Journal of Lightwave Technology, 24, 2179-2183(2006).

[15] Bai Y, Yan F P, Feng T et al. Demonstration of linewidth measurement based on phase noise analysis for a single-frequency fiber laser in the 2 μm band[J]. Laser Physics, 29, 075102(2019).

[16] Feng T, Ding D L, Zhao Z W et al. Switchable 10 nm-spaced dual-wavelength SLM fiber laser with subkHz linewidth and high OSNR using a novel multiple-ring configuration[J]. Laser Physics Letters, 13, 105104(2016).

[17] Feng T, Jiang M L, Wei D et al. Four-wavelength switchable SLM fiber laser with sub-kHz linewidth using superimposed high-birefringence FBG and dual-coupler ring-based compound cavity filter[J]. Optics Express, 27, 36662-36679(2019).

[18] Feng T, Wei D, Bi W et al. Wavelength-switchable ultra-narrow linewidth fiber laser enabled by a figure-8 compound-ring-cavity filter and polarization-managed four-channel filter[J]. Optics Express, 29, 31179-31200(2021).

[19] Guo Y, Yan F P, Feng T et al. Wavelength-switchable single-longitudinal-mode thulium-doped fiber laser at 2.05 µm using a superimposed fiber Bragg grating[J]. Infrared Physics and Technology, 122, 104058(2022).

[20] Han W G, Yan F P et al. Wavelength-switchable single-longitudinal-mode thulium-doped fiber laser with sampled fiber Bragg gratings[J]. IEEE Access, 9, 62212-62218(2021).

[21] Li Q, Yan F P, Peng W J et al. Single-frequency ring-cavity Tm-doped fiber laser based on CMFBG filter[J]. Laser Physics Letters, 10, 095105(2013).

[22] Bai Y, Yan F P, Sun J H et al. Single-longitudinal-mode thulium-doped fiber laser using Fabry-Perot filter and saturable absorber[J]. Science & Technology Review, 34, 104-107(2016).

[23] Bai Y, Yan F P, Feng T et al. Ultra-narrow-linewidth fiber laser in 2 μm band using saturable absorber based on PM-TDF[J]. Chinese Journal of Lasers, 46, 0101003(2019).

[24] Feng S, Mao Q, Tian Y et al. Widely tunable single longitudinal-mode fiber laser with a cascaded fiber ring secondary cavity[J]. IEEE Photonics Technology Letters, 25, 323-326(2013).

[25] Zhang L N, Yan F P, Feng T et al. Six-wavelength-switchable narrow-linewidth thulium-doped fiber laser with a polarization-maintaining sampled fiber Bragg grating[J]. Optics and Laser Technology, 136, 106788(2021).

[26] Guo B, Guo X Y, Tang L G et al. Ultralong-period grating-based multiwavelength ultrafast fiber laser[J]. Chinese Optics Letters, 19, 071405(2021).

[27] Feng T, Ding D L, Yan F P et al. Widely tunable single-/ dual-wavelength fiber lasers with ultra-narrow linewidths and high OSNR using a high-quality passive subring cavity and novel tuning method[J]. Optics Express, 24, 19760-19768(2016).

[28] Cheng D, Yan F P, Feng T et al. A six-wavelength-switchable SLM thulium-doped fiber laser was enabled by the sampled FBGs and a 3 × 3 coupler-based dual-ring compound cavity filter[J]. IEEE Photonics Journal, 14, 1515908(2022).

[29] Wang Z K, Shang J M, Mu K L et al. A single-longitudinal-mode fiber laser with ultra-narrow linewidth and extremely high stability was obtained using a triple-ring passive substrate resonator[J]. Optics and Laser Technology, 130, 106329(2020).

[30] Cranch G A. Frequency noise reduction in erbium-doped fiber distributed-feedback lasers by electronic feedback[J]. Optics Letters, 27, 1114-1116(2002).

[31] Zhang J L, Yue C Y, Schinn G W et al. Stable single-mode compound-ring erbium-doped fiber laser[J]. Journal of Lightwave Technology, 14, 104-109(1996).

[32] Xu D, Yang F, Chen D J et al. Laser phase and frequency noise measurements were performed using a Michelson interferometer composed of a 3×3 optical fiber coupler[J]. Optics Express, 23, 22386-22393(2015).

[33] Wang X, Yan F P, Han W G. Single longitudinal mode narrow linewidth thulium-doped fiber laser with special subring cavity[J]. Chinese Journal of Lasers, 46, 0901001(2019).