Koplow J P, Kliner D A V, Goldberg L. Single-mode operation of a coiled multimode fiber amplifier [J]. Opt. Lett., 2000, 25(7): 442.？
[2]
Kelson J, Hardy A A. Strong pumped fiber amplifiers [J]. IEEE J. Quantum Electronics, 1998, 34: 1570.？
[3]
Hardy A A, Oron R. Signal amplification in strongly pumped fiber amplifiers [J]. IEEE J. Quantum Electron. , 1997,33(3): 307.？
[4]
Lou Qihong, Zhou Jun, Kong Lingfeng, et al. Recent progress of high power pulsed double cladding fiber lasers [J]. Chinese Journal of Quantum Electronics (量子电子学报), 2005, 22(4): 510.？
[5]
Limpert L, Zellmer H, Tünnermann A. Suppression of high order modes in a multimode fiber amplifier using efficient gain-loss-management (GLM), in Advanced Solid-State Lasers, Québec City, Canada, 2002, MB20: 112.？
[6]
Hardy A A, Oron R. Amplified spontaneous emission and Rayleigh backscattering in strong pumped fiber amplifiers [J], J. Lightw. Technol., vol. 16, no. 10, pp. 1865-1873, Oct. 1998.？
[7]
Gong Mali, Yuan Yanyang, Li Chen, et al. Numerical modeling of transverse mode competition in strongly pumped multimode fiber lasers and amplifiers [J]. Optics Express, 2007, 15(6): 3236.？
[8]
Galvanauskas A. Mode-Scalable Fiber-Based Chirped Pulse Amplification Systems [J]. IEEE J. Quantum Electronics, 2001, 7(4): 504.？
[9]
Paschotta R, Nilsson J, Tropper A C, et al. Ytterbium-doped fiber amplifier [J]. IEEE J. Quantum Electronics, 1997, 33(7): 1049.
