[1] Jauregui C, Limpert J, Tünnermann A. High-power fibre lasers[J]. Nature Photonics, 2013, 7(11): 861-867.

[2] Zervas M N, Codemard C A. High power fiber lasers: a review[J]. IEEE Journal of Selected Topics in Quantum Electronics, 2014, 20(5): 219-241.

[3] Limpert J, Stutzki F, Jansen F, et al. Yb-doped large-pitch fibres: effective single-mode operation based on higher-order mode delocalisation[J]. Light: Science & Applications, 2012, 1(4): e8.

[4] Hu M, Quan Z, Wang J H, et al. Stimulated Brillouin scattering threshold dependent on temporal characteristics in a kilowatt-peak-power, single-frequency nanosecond pulsed fiber amplifier[J]. Chinese Optics Letters, 2016, 14(3): 031403.

[5] Koponen J, Söderlund M, Hoffman H J, et al. Photodarkening measurements in large mode area fibers[J]. Proceedings of SPIE, 2007, 6453: 64531E.

[6] Jetschke S, Unger S, Schwuchow A, et al. Efficient Yb laser fibers with low photodarkening by optimization of the core composition[J]. Optics Express, 2008, 16(20): 15540-15545.

[7] Eidam T, Wirth C, Jauregui C, et al. Experimental observations of the threshold-like onset of mode instabilities in high power fiber amplifiers[J]. Optics Express, 2011, 19(14): 13218-13224.

[8] Tao R M, Ma P F, Wang X L, et al. 1.3 kW monolithic linearly polarized single-mode master oscillator power amplifier and strategies for mitigating mode instabilities[J]. Photonics Research, 2015, 3(3): 86-93.

[9] Petit V, Tumminelli R P, Minelly J D, et al. Extremely low NA Yb doped preforms (<0.03) fabricated by MCVD[J]. Proceedings of SPIE, 2016, 9728: 97282R.

[10] Jauregui C, Otto H J, Modsching N, et al. Recent progress in the understanding of mode instabilities[J]. Proceedings of SPIE, 2015, 9344: 93440J.

[11] Ma X Q, Zhu C, Hu I N, et al. Single-mode chirally-coupled-core fibers with larger than 50 μm diameter cores[J]. Optics Express, 2014, 22(8): 9206-9219.

[12] Gu G C, Kong F T, Hawkins T, et al. Ytterbium-doped large-mode-area all-solid photonic bandgap fiber lasers[J]. Optics Express, 2014, 22(11): 13962-13968.

[13] Jain D, Jung Y, Nunez-Velazquez M, et al. Extending single mode performance of all-solid large-mode-area single trench fiber[J]. Optics Express, 2014, 22(25): 31078-31091.

[14] Stutzki F, Jansen F, Liem A, et al. 26 mJ, 130 W Q-switched fiber-laser system with near-diffraction-limited beam quality[J]. Optics Letters, 2012, 37(6): 1073-1075.

[15] Brooks C D, di Teodoro F. Multimegawatt peak-power, single-transverse-mode operation of a 100 μm core diameter, Yb-doped rodlike photonic crystal fiber amplifier[J]. Applied Physics Letters, 2006, 89(11): 111119.

[16] Jain D, Jung Y M, Barua P, et al. Demonstration of ultra-low NA rare-earth doped step index fiber for applications in high power fiber lasers[J]. Optics Express, 2015, 23(6): 7407-7415.

[17] Beier F, Hupel C, Kuhn S, et al. Single mode 4.3 kW output power from a diode-pumped Yb-doped fiber amplifier[J]. Optics Express, 2017, 25(13): 14892-14899.

[18] Peng K, Zhan H, Ni L, et al. Single-mode large-mode-area laser fiber with ultralow numerical aperture and high beam quality[J]. Applied Optics, 2016, 55(35): 10133-10137.

[19] Kong F T, Dunn C, Parsons J, et al. Large-mode-area fibers operating near single-mode regime[J]. Optics Express, 2016, 24(10): 10295-10301.

[20] Xu W B, Lin Z Q, Wang M, et al. 50 μm core diameter Yb 3+/Al 3+/F - codoped silica fiber with M2<1.1 beam quality [J]. Optics Letters, 2016, 41(3): 504-507.

[21] Likhachev ME, Aleshkina SS, Shubin AV, et al. Large-mode-area highly Yb-doped photodarkening-free Al2O3-P2O5-SiO2-based fiber[C]∥CLEO/Europe and EQEC 2011 Conference Digest, May 22-26, 2011, Munich, Germany. Washington, D.C.: OSA, 2011: CJ_P24.

[22] Liu S J, Li H Y, Tang Y X, et al. Fabrication and spectroscopic properties of Yb 3+-doped silica glasses using the sol-gel method [J]. Chinese Optics Letters, 2012, 10(8): 081601.

[23] 刘少俊. 溶胶-凝胶法制备掺镱石英玻璃和光子晶体光纤的研究[D]. 上海: 中国科学院大学, 2012.

    Liu SJ. Investigation on fabrication and spectroscopic properties of Yb 3+-doped silica glass and PCF fiber by sol-gel method [D]. Shanghai: University of Chinese Academy of Sciences, 2012.

[24] 王世凯. Sol-Gel法制备Yb 3+掺杂石英玻璃及大模场光子晶体光纤的研究 [D]. 上海: 中国科学院大学, 2014.

    Wang SK. Study on fabrication of Yb 3+-doped silica glass and its large mode area photonic crystal fiber by sol-gel method [D]. Shanghai: University of Chinese Academy of Sciences, 2014.

[25] 楼风光. 溶胶凝胶法制备掺Yb 3+,Tm 3+石英玻璃芯棒及大模场光纤的研究 [D]. 上海: 中国科学院大学, 2014.

    Lou FG. Study on fabrication of Yb 3+, Tm 3+-doped silica glass core rod and its large mode area fiber prepared by sol-gel method [D]. Shanghai: University of Chinese Academy of Sciences, 2014.

[26] 许文彬. Sol-gel 法结合粉末烧结制备掺Yb 3+石英玻璃及大模场光纤的研究 [D]. 上海: 中国科学院大学, 2017.

    Xu WB. Study on performance of Yb 3+-doped silica glass and its large mode area fiber prepared by sol-gel method combing powder sintering [D]. Shanghai: University of Chinese Academy of Sciences, 2017.

[27] 胡丽丽, 王世凯, 楼风光, 等. 掺Yb石英光纤预制棒芯棒的制备方法: 201310294400.3[P].2013-10-30.

    Hu LL, Wang SK, Lou FG, et al. The preparation method of Yb-doped silica fiber core rode: 201310294400.3[P]. 2013-10-30.

[28] Wang S, Lou F, Yu C, et al. Influence of Al 3+ and P 5+ ion contents on the valence state of Yb 3+ ions and the dispersion effect of Al 3+ and P 5+ ions on Yb 3+ ions in silica glass [J]. Journal of Materials Chemistry C, 2014, 22(2): 4406-4414.

[29] Xu W B, Ren J J, Shao C Y, et al. Effect of P 5+ on spectroscopy and structure of Yb 3+/Al 3+/P 5+ co-doped silica glass [J]. Journal of Luminescence, 2015, 167: 8-15.

[30] Xu W B, Yu C L, Wang S K, et al. Effects of F - on the optical and spectroscopic properties of Yb 3+/Al 3+-co-doped silica glass [J]. Optical Materials, 2015, 42: 245-250.

[31] Wang F, Shao C Y, Yu C L, et al. Effect of AlPO4 join concentration on optical properties and radiation hardening performance of Yb-doped Al2O3-P2O5-SiO2 glass[J]. Journal of Applied Physics, 2019, 125(17): 173104.

[32] KeckD, SchultzP, Zimar F. Method of forming optical waveguide fibers: US3737292[P/OL].1973-06-05[2019-05-01]. https:∥patents.google.com/patent/US3737292.

[33] Webb A S, Boyland A J, Standish R J, et al. MCVD in situ solution doping process for the fabrication of complex design large core rare-earth doped fibers[J]. Journal of Non-Crystalline Solids, 2010, 356(18/19): 848-851.

[34] LenardicB, KvederM. Advanced vapor-phase doping method using chelate precursor for fabrication of rare earth-doped fibers[C]∥Optical Fiber Communication Conference and National Fiber Optic Engineers Conference, March 22-26, 2009, San Diego, California, United States. Washington, D.C.: OSA, 2009: OThK6.

[35] TammelaS, KiiveriP, SarkilahtiS, et al. Direct nanoparticle deposition process for manufacturing very short high gain Er-doped silica glass fibers[C]∥2002 28TH European Conference on Optical Communication, September 8-12, 2002, Copenhagen, Denmark. New York: IEEE, 2002: 9084348.

[36] Leich M, Just F, Langner A, et al. Highly efficient Yb-doped silica fibers prepared by powder sinter technology[J]. Optics Letters, 2011, 36(9): 1557-1559.

[37] Benoit A, Dauliat R, Schuster K, et al. Optical fiber microstructuration for strengthening single-mode laser operation in high power regime[J]. Optical Engineering, 2014, 53(7): 071817.

[38] Langner A, Schotz G, Such M, et al. A new material for high-power laser fibers[J]. Proceedings of SPIE, 2008, 6873: 687311.

[39] Langner A, Such M, Schotz G, et al. Design evolution, long term performance and application tests of extra large mode area (XLMA) fiber lasers[J]. Proceedings of SPIE, 2013, 8601: 86010G.

[40] Zhang W, Liu J T, Zhou G Y, et al. Optical properties of the Yb/Er co-doped silica glass prepared by laser sintering technology[J]. Optical Materials Express, 2017, 7(5): 1708-1715.

[41] Chen Y, Zhao N, Liu J T, et al. Yb 3+-doped large-mode-area photonic crystal fiber for fiber lasers prepared by laser sintering technology [J]. Optical Materials Express, 2019, 9(3): 1356-1364.

[42] Liu S, Wang M, Zhou Q L, et al. Ytterbium-doped silica photonic crystal fiber laser fabricated by the nanoporous glass sintering technique[J]. Laser Physics, 2014, 24(6): 065801.

[43] Yang K, Zheng S P, Jiang X B, et al. Luminescence and scintillation of high silica glass containing SnO[J]. Materials Letters, 2017, 204: 5-7.

[44] Chu Y B, Ma Y X, Yang Y, et al. Yb 3+-doped large core silica fiber for fiber laser prepared by glass phase-separation technology [J]. Optics Letters, 2016, 41(6): 1225-1228.

[45] Chu Y B, Yang Y, Hu X W, et al. Yb 3+ heavily doped photonic crystal fiber lasers prepared by the glass phase-separation technology [J]. Optics Express, 2017, 25(20): 24061-24067.

[46] Pedrazza U, Romano V, Lüthy W. Yb 3+∶ Al 3+∶ sol-gel silica glass fiber laser [J]. Optical Materials, 2007, 29(7): 905-907.

[47] El Hamzaoui H, Courthéoux L, Nguyen V N, et al. From porous silica xerogels to bulk optical glasses: the control of densification[J]. Materials Chemistry and Physics, 2010, 121(1/2): 83-88.

[48] Baz A, El Hamzaoui H, Fsaifes I, et al. A pure silica ytterbium-doped sol-gel-based fiber laser[J]. Laser Physics Letters, 2013, 10(5): 055106.

[49] El Hamzaoui H, Bouwmans G, Cassez A, et al. F/Yb-codoped sol-gel silica glasses: toward tailoring the refractive index for the achievement of high-power fiber lasers[J]. Optics Letters, 2017, 42(7): 1408-1411.

[50] Li Y G, Huang J P, Li Y F, et al. Optical properties and laser output of heavily Yb-doped fiber prepared by sol-gel method and DC-RTA technique[J]. Journal of Lightwave Technology, 2008, 26(18): 3256-3260.

[51] Wang M, Wang F, Feng S, et al. 272 W quasi single-mode picosecond pulse laser of ytterbium-doped large-mode-area photonic crystal fiber[J]. Chinese Optics Letters, 2019, 17(7): 071401.

[52] Wang S K, Li Z L, Yu C L, et al. Fabrication and laser behaviors of Yb 3+ doped silica large mode area photonic crystal fiber prepared by sol-gel method [J]. Optical Materials, 2013, 35(9): 1752-1755.

[53] Wang S K, Feng S Y, Wang M, et al. Optical and laser properties of Yb 3+-doped Al2O3-P2O5-SiO2 large-mode-area photonic crystal fiber prepared by the sol-gel method [J]. Laser Physics Letters, 2013, 10(11): 115802.

[54] Xu W B, Wang M, Feng S Y, et al. Fabrication and laser amplification behavior of Yb 3+/Al 3+ co-doped photonic crystal fiber [J]. IEEE Photonics Technology Letters, 2016, 28(4): 391-393.

[55] Wang F, Hu L, Xu W, et al. Manipulating refractive index, homogeneity and spectroscopy of Yb 3+-doped silica-core glass towards high-power large mode area photonic crystal fiber lasers [J]. Optics Express, 2017, 25(21): 25960-25969.

[56] WangF, WangM, Feng SY, et al. Large-mode-area photonic crystal fiber towards pulse laser amplification based on YbAl/P/F codoped silica glass[C]∥Advanced Solid State Lasers 2018, November 4-8, 2018, Boston, Massachusetts, United States. Washington, D.C.: OSA, 2018: ATh1A. 5.

[57] Wang S K, Xu W B, Lou F G, et al. Spectroscopic and laser properties of Al-P co-doped Yb silica fiber core-glass rod and large mode area fiber prepared by sol-gel method[J]. Optical Materials Express, 2016, 6(1): 69-78.

[58] Lin Z Q, Lou F G, Wang M, et al. A diffraction-limited laser of 25/400 Yb 3+/Al 3+/P 5+/F - silica fiber with a zigzag refractive index profile [J]. Laser physics, 2017, 27(8): 085106.

[59] Wang S K, Xu W B, Wang F, et al. Yb 3+-doped silica glass rod with high optical quality and low optical attenuation prepared by modified sol-gel technology for large mode area fiber [J]. Optical Materials Express, 2017, 7(6): 2012-2022.

[60] 王孟, 王璠, 于春雷, 等. 兆瓦峰值功率输出的超低纤芯数值孔径大模场光子晶体光纤[J]. 光学学报, 2019, 39(5): 0536001.

    Wang M, Wang F, Yu C L, et al. Ultra-low core numerical aperture large mode area photonic crystal fiber with 1 MW peak power output[J]. Acta Optica Sinica, 2019, 39(5): 0536001.

[61] Kosinski S G, Krol D M, Duncan T M, et al. Raman and NMR spectroscopy of SiO2 glasses co-doped with Al2O3 and P2O5[J]. Journal of Non-Crystalline Solids, 1988, 105(1/2): 45-52.