Compared with traditional uniform fibers, tapered fiber has numerous unique advantages, such as larger mode area, higher pump absorption, suppression to nonlinear effects, and maintaining good beam quality. In this manuscript, we have constructed an all-fiberized fiber amplifier which is based on a piece of ytterbium-doped tapered double-clad fiber (T-DCF). The fiber amplifier is operated under continuous wave (CW) regime at 1080 nm wavelength. The $M^{2}$ factor of the amplifier at 1.39 kW output power is ${\sim}1.8$. The maximum output power of the system reached 1.47 kW, which, to the best of our knowledge, is the highest output power of long tapered fiber based fiber laser system. Our result successfully verifies the potential of power scalability and all-fiberized capability of long tapered fiber, and the performance of our system can be further enhanced by fiber design optimization.

中文翻译：

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由有源长锥形光纤实现的千瓦级高功率光纤激光器

与传统的均匀光纤相比，锥形光纤具有模式面积大、泵浦吸收高、抑制非线性效应、保持良好的光束质量等诸多独特优势。在这份手稿中，我们构建了一个基于掺镱锥形双包层光纤 (T-DCF) 的全光纤放大器。光纤放大器在 1080 nm 波长的连续波 (CW) 状态下运行。这$M^{2}$放大器在 1.39 kW 输出功率下的系数为${\sim}1.8$. 该系统的最大输出功率达到了1.47 kW，据我们所知，这是基于长锥形光纤的光纤激光系统的最高输出功率。我们的结果成功地验证了长锥形光纤的功率可扩展性和全光纤化能力的潜力，并且我们的系统的性能可以通过光纤设计优化进一步提高。