[1] Liu J, Liu C, Shi H X et al. 203 W all-polarization maintaining picosecond thulium-doped all-fiber laser[J]. Acta Physica Sinica, 65, 194208(2016).

[2] Swofford R L, Albrecht A C. Nonlinear spectroscopy[J]. Annual Review of Physical Chemistry, 29, 421-440(1978).

[3] Rota-Rodrigo S, Ibañez I, López-Amo M. Multi-wavelength fiber laser in single-longitudinal mode operation using a photonic crystal fiber Sagnac interferometer[J]. Applied Physics B, 110, 303-308(2013).

[4] Yan Z Y, Sun B, Li X H et al. Widely tunable Tm-doped mode-locked all-fiber laser[J]. Scientific Reports, 6, 27245(2016). http://www.nature.com/articles/srep27245

[5] Azimipour M, Pashaie R. Nonlinear optical signal processing on multiwavelength sensitive materials[J]. Optics Letters, 38, 4324-4326(2013). http://europepmc.org/abstract/med/24177084

[6] Keller U. Recent developments in compact ultrafast lasers[J]. Nature, 424, 831-838(2003). http://www.ncbi.nlm.nih.gov/pubmed/12917697

[7] Liu J, Xu J, Wang Q et al. High-pulse-energy passively mode-locked 2.0 μm thulium-doped ultrafast all-fiber laser[J]. Chinese Journal of Lasers, 39, 0602009(2012).

[8] Liu J, Tan F Z, Liu C et al. Progress on high-power ultrashort-pulsed thulium-doped fiber lasers[J]. Chinese Journal of Lasers, 44, 0201003(2017).

[9] Solodyankin M A, Obraztsova E D, Lobach A S et al. Mode-locked 1.93 μm thulium fiber laser with a carbon nanotube absorber[J]. Optics Letters, 33, 1336-1338(2008). http://www.ncbi.nlm.nih.gov/pubmed/18552950

[10] Fang Q, Kieu K, Peyghambarian N. An all-fiber 2-μm wavelength-tunable mode-locked laser[J]. IEEE Photonics Technology Letters, 22, 1656-1658(2010). http://ieeexplore.ieee.org/document/5582205/

[11] Jin X X, Wang X, Wang X L et al. Tunable multiwavelength mode-locked Tm/Ho-doped fiber laser based on a nonlinear amplified loop mirror[J]. Applied Optics, 54, 8260-8264(2015).

[12] Yang G, Liu Y G, Wang Z et al. Broadband wavelength tunable mode-locked thulium-doped fiber laser operating in the 2 μm region by using a graphene saturable absorber on microfiber[J]. Laser Physics Letters, 13, 065105(2016).

[13] Kneis C, Donelan B, Berrou A et al. Actively mode-locked Tm 3+-doped silica fiber laser with wavelength-tunable, high average output power[J]. Optics Letters, 40, 1464-1467(2015).

[14] Xu Z, Dou Z Y, Hou J et al. All-fiber wavelength-tunable Tm-doped fiber laser mode locked by SESAM with 120 nm tuning range[J]. Applied Optics, 56, 5978-5981(2017).

[15] Mashiko Y, Fujita E, Tokurakawa M. Tunable noise-like pulse generation in mode-locked Tm fiber laser with a SESAM[J]. Optics Express, 24, 26515-26520(2016). http://europepmc.org/abstract/med/27857384

[16] Sun B, Luo J Q, Yan Z Y et al. 1867-2010 nm tunable femtosecond thulium-doped all-fiber laser[J]. Optics Express, 25, 8997-9002(2017). http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-25-8-8997

[17] Ma W Z, Wang T S, Zhang Y et al. Widely tunable 2 μm continuous-wave and mode-locked fiber laser[J]. Applied Optics, 56, 3342-3346(2017). http://www.ncbi.nlm.nih.gov/pubmed/28430255

[18] Kivisto S, Hakulinen T, Guina M et al. Tunable Raman soliton source using mode-locked Tm-Ho fiber laser[J]. IEEE Photonics Technology Letters, 19, 934-936(2007). http://ieeexplore.ieee.org/document/4214869/

[19] McComb T S, Sims R A, Willis C C et al. . High-power widely tunable thulium fiber lasers[J]. Applied Optics, 49, 6236-6242(2010). http://www.ncbi.nlm.nih.gov/pubmed/21068854

[20] Frazão O. Baptista J M T, Santos J L. Recent advances in high-birefringence fiber loop mirror sensors[J]. Sensors, 7, 2970-2983(2007).

[21] Noda J, Okamoto K, Sasaki Y. Polarization-maintaining fibers and their applications[J]. Journal of Lightwave Technology, 4, 1071-1089(1986). http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1074847

[22] Mortimore D B. Fiber loop reflectors[J]. Journal of Lightwave Technology, 6, 1217-1224(1988).

[23] Álvarez-Tamayo R I, Durán-Sánchez M, Pottiez O et al. . Theoretical and experimental analysis of tunable Sagnac high-birefringence loop filter for dual-wavelength laser application[J]. Applied Optics, 50, 253-260(2011).

[24] Álvarez-Tamayo R I, Durán-Sánchez M, Pottiez O et al. . A dual-wavelength tunable laser with superimposed fiber Bragg gratings[J]. Laser Physics, 23, 055104(2013). http://adsabs.harvard.edu/abs/2013LaPhy..23e5104A