Opt Express. 2023 Mar 13;31(6):10586-10595. doi: 10.1364/OE.472487.
A high-power linearly-polarized all-fiber single-frequency amplifier at 1 µm based on tandem core-pumping is demonstrated by using a large-mode-area Ytterbium-doped fiber with a core diameter of 20 µm, which nicely balances the stimulated Brillouin scattering effect, thermal load, and output beam quality. A maximum output power of more than 250 W with a corresponding slope efficiency of >85% is achieved at the operating wavelength of 1064 nm without being constrained by the saturation and nonlinear effects. Meanwhile, a comparable amplification performance is realized with a lower injection signal power of the wavelength near the peak gain of the Yb-doped fiber. The polarization extinction ratio and the M factor of the amplifier are respectively measured to be >17 dB and 1.15 under the maximal output power. In addition, by virtue of the single-mode 1018 nm pump laser, the intensity noise of the amplifier under maximal output power is measured to be comparable to that of the single-frequency seed laser at frequencies higher than 2 kHz, except for the emergence of parasitic peaks that can be eliminated by optimizing the driving electronics of the pump lasers, while the deterioration of the amplification process to the frequency noise and linewidth of the laser is negligible. To the best of our knowledge, this is the highest output power of a single-frequency all-fiber amplifier based on the core-pumping scheme.
基于双包层抽运的 1 µm 高功率线偏振全光纤单频放大器通过使用纤芯直径为 20 µm 的大模场掺镱光纤得以实现，该光纤很好地平衡了受激布里渊散射效应、热负载和输出光束质量。在 1064nm 的工作波长下，实现了超过 250W 的最大输出功率，相应的斜率效率>85%，而不会受到饱和和非线性效应的限制。同时，在接近掺镱光纤峰值增益的波长下，通过较低的注入信号功率，实现了可比拟的放大性能。在最大输出功率下，放大器的偏振消光比和 M 因子分别测量为>17dB 和 1.15。此外，通过单模 1018nm 抽运激光，在高于 2kHz 的频率下，测量到放大器在最大输出功率下的强度噪声与单频种子激光相当，除了出现寄生峰外，这些寄生峰可以通过优化抽运激光器的驱动电子设备来消除，而放大过程对激光的频率噪声和线宽的恶化可以忽略不计。据我们所知，这是基于芯抽运方案的单频全光纤放大器的最高输出功率。
