Guan Xianchao, Yang Changsheng, Lin Wei, Zhao Qilai, Tan Tianyi, Gu Quan, Zhou Kaijun, Wei Xiaoming, Yang Zhongmin, Xu Shanhui
Opt Lett. 2020 Oct 1;45(19):5484-5487. doi: 10.1364/OL.402590.
In this Letter, a bidirectional amplifier configuration suppressing the relative intensity noise in a 1950-nm linearly polarized single-frequency fiber laser (SFFL) is proposed. The scheme to amplify the signal in a nonlinear saturated amplification regime with low gain distribution for suppressing the RIN is theoretically analyzed. By optimizing the input power level and reflectivity of the bidirectional power-amplifier, the RIN is decreased maximally by >24 within the frequency range of 200 kHz. A stable output power of over 5.16 W with a polarization extinction ratio of 21.2 dB is obtained. Additionally, the amplified signal maintains a linewidth of 7.1 kHz nearly identical with that of the seed, both with a signal-to-noise ratio of more than 60 dB. This all-optical technique on noise suppression applied to the fiber amplifier paves the way to realize low-noise SFFL with power improvement.
在本信函中，提出了一种抑制1950纳米线性偏振单频光纤激光器（SFFL）中相对强度噪声的双向放大器配置。从理论上分析了在具有低增益分布的非线性饱和放大状态下放大信号以抑制相对强度噪声（RIN）的方案。通过优化双向功率放大器的输入功率水平和反射率，在200千赫兹频率范围内，相对强度噪声最大降低超过24。获得了超过5.16瓦的稳定输出功率，偏振消光比为21.2分贝。此外，放大后的信号保持7.1千赫兹的线宽，与种子信号的线宽几乎相同，两者的信噪比均超过60分贝。这种应用于光纤放大器的全光噪声抑制技术为实现功率提升的低噪声单频光纤激光器铺平了道路。
