In this work, we realize a high-power, narrow linewidth, linearly polarized laser output based on a compact all-fiber polarization maintaining (PM) master oscillator power amplifier. The seed is a fiber oscillator laser (FOL) with few-longitudinal-mode for spectral broadening suppression. The spectral broadening characteristics in the FOL seed and in the PM-amplifier with different pumping schemes are studied experimentally and theoretically. The effect of different types of fibers in the amplifier on spectral broadening is also analysed theoretically. Finally, we demonstrate a narrow linewidth linearly polarized all-fiber amplifier operating at the maximum output power of 3.08 kW with a 3 dB linewidth of 0.2 nm. The polarization extinction ratio is measured to be larger than 93.5% and the M2 maintains lower than 1.45 in the power scaling process. To the best of our knowledge, this is the highest demonstrated output power for narrow linewidth linearly polarized all-fiber lasers with the charactristics of low cost and a compact structure.

中文翻译：

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基于紧凑型 MOPA 结构的 3 kW、0.2 nm 窄线宽线偏振全光纤激光器

在这项工作中，我们基于紧凑型全光纤保偏 (PM) 主振荡器功率放大器实现了高功率、窄线宽、线偏振激光输出。种子是光纤振荡器激光器 (FOL)，具有用于光谱展宽抑制的少数纵向模式。通过实验和理论研究了 FOL 种子和具有不同泵浦方案的 PM 放大器中的光谱展宽特性。还从理论上分析了放大器中不同类型光纤对频谱展宽的影响。最后，我们展示了一种窄线宽线性极化全光纤放大器，其最大输出功率为 3.08 kW，3 dB 线宽为 0.2 nm。测量偏振消光比大于93.5%，在功率缩放过程中M2保持低于1.45。