The fiber laser based on an oscillating-amplifying integrated structure has the potential to benefit from the advantages of a fiber laser oscillator and amplifier with the characteristics of strong anti-back-reflected light ability and high efficiency. Here, we achieved a 3.5-kW near-single-mode (M2 ∼ 1.24) oscillating–amplifying integrated fiber laser with an active fiber length of 8 m in the oscillating section and 17.6 m in the amplifying section. While operating at the maximum power, the optical-to-optical conversion efficiency is 87.0%, and the intensity of stimulated Raman scattering is about 23.61 dB lower than that of the signal light. To the best of the authors’ knowledge, this is the highest output power of an oscillating–amplifying integrated fiber laser, accompanied with the best beam quality and the highest efficiency.

中文翻译：

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3.5kW 近单模振荡放大集成光纤激光器

基于振荡放大一体化结构的光纤激光器具有抗背反射光能力强、效率高等特点，有望受益于光纤激光振荡器和放大器的优点。在这里，我们实现了 3.5 kW 的近单模（米2∼ 1.24) 振荡放大一体化光纤激光器，振荡部分的有效光纤长度为 8 m，放大部分的有效光纤长度为 17.6 m。在最大功率工作时，光光转换效率为87.0%，受激拉曼散射强度比信号光低约23.61 dB。据作者所知，这是振荡放大集成光纤激光器的最高输出功率，同时具有最佳光束质量和最高效率。