In this Letter, we have demonstrated a triple-cladded fiber (TCF)-based master oscillator power amplifier (MOPA), with an output power scaling up to 4.67 kW, an optical-to-optical efficiency of 78%, and a beam quality factor ${{\rm M}^2}$ of 1.57. The MOPA output power was limited by stimulated Raman scattering (SRS) of which our design yielded a 31.2 dB suppression ratio at the 4.67 kW output power. Such a unique design of a TCF-based structure allows a wide range of flexibility over fiber parameters, mitigation of nonlinear effects, low-loss splice integration, reliable high-power pump guiding in turn, and an ease in overall thermal management at multi-kW output power levels. Together with direct diode-pumping configuration, TCF-based designs promise thermally and mechanically robust, compact, and highly efficient MOPA systems of a superior beam quality.

中文翻译：

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二极管泵浦三包层光纤MOPA，输出功率可扩展至4.67 kW

在这封信中，我们演示了基于三重包层光纤（TCF）的主振荡器功率放大器（MOPA），其输出功率可缩放至4.67 kW，光-光效率为78％，并且光束质量因素$ {{\\ M M} ^ 2} $1.57。MOPA输出功率受到受激拉曼散射（SRS）的限制，我们的设计在4.67 kW输出功率下产生了31.2 dB的抑制比。这种基于TCF的结构的独特设计可在光纤参数上提供广泛的灵活性，减轻非线性影响，低损耗的熔接集成，可靠的大功率泵引导，并简化了多通道系统的整体热管理kW输出功率水平。结合直接二极管泵浦配置，基于TCF的设计保证了具有优异光束质量的热和机械坚固，紧凑和高效的MOPA系统。