[1] Paschotta R, Nilsson J, Tropper A C et al. Ytterbium-doped fiber amplifiers[J]. IEEE Journal of Quantum Electronics, 33, 1049-1056(1997).

[2] Zhou P, Leng J Y, Xiao H et al. High average power fiber lasers: research progress and future prospect[J]. Chinese Journal of Lasers, 48, 2000001(2021).

[3] Snitzer E, Po H, Hakimi F et al. Double clad, offset core Nd fiber laser[C], PD5(1988).

[4] Xiao Q R, Tian J D, Li D et al. Tandem-pumped high-power ytterbium-doped fiber lasers: progress and opportunities[J]. Chinese Journal of Lasers, 48, 1501004(2021).

[5] Li F Y, Li Y, Song H Q et al. The national optical fiber material devices achieve high SRS rejection ratio of 20.88 kW output[J]. Chinese Journal of Lasers, 48, 2116002(2021).

[6] Li F Y, Dai J Y, Liu N et al. Self developed fiber optic achieves high SRS suppression of 21.39 kW laser output[J]. Chinese Journal of Lasers, 49, 2016004(2022).

[7] Xiao H, Pan Z Y, Chen Z L et al. Stable output of 20 kW high beam quality laser based on self-developed optical fiber and device[J]. Chinese Journal of Lasers, 49, 210-211(2022).

[8] Huang Z H, Cao J Q, Guo S F et al. Comparison of fiber lasers based on distributed side-coupled cladding-pumped fibers and double-cladding fibers[J]. Applied Optics, 53, 2187-2195(2014).

[9] Huang Z H, Cao J Q, Chen J B. Research progress on high-power GTWave fiber lasers[J]. Chinese Journal of Lasers, 48, 0401010(2021).

[10] Norman S, Zervas M N, Appleyard A et al. Latest development of high-power fiber lasers in SPI[J]. Proceedings of SPIE, 5335, 229-237(2004).

[11] Lin A X, Zhan H, Peng K et al. 10 kW-level pump-gain integrated functional laser fiber[J]. High Power Laser and Particle Beams, 30, 060101(2018).

[12] Gao C, Liu N, Li F Y et al. 17.4 kW (1+1) long distance side-pumped laser fiber[J]. High Power Laser and Particle Beams, 34, 051002(2022).

[13] Stiles E. New developments in IPG fiber laser technology[C](2009).

[14] Li F Y, Gao C, Liu N et al. Ultra high power fiber laser employing homemade (1+1) side-pumped fiber and tandem-pumping technique[J]. Proceedings of SPIE, 12595, 125951Z(2023).

[15] Li Y W, Liu Y, Li F Y et al. Design and fabrication of >20 kW 5×1 pump combiner with high efficiency[J]. Optics & Laser Technology, 163, 109453(2023).

[16] Huang S, Wu W J, Li F Y et al. A duplexed CTFBG with broad bandwidth for SRS suppression in high power lasers[C], JW3B.58(2022).