Influence of stimulated Brillouin scattering on the noise evolution of high-power all-fiber singlefrequency MOPA system

作者：Guan, Xianchao; Yang, Changsheng^*; Ma, Pengfei; Zhao, Qilai; Zhang, Zhitao; Lin, Wei; Wei, Xiaoming; Yang, Zhongmin; Xu, Shanhui

来源：Optics and Laser Technology, 2020, 128: 106212.

DOI：10.1016/j.optlastec.2020.106212

• Single-frequency fiber laser
• Master-oscillation power amplifier
• Relative intensity-noise
• Stimulated Brillouin scattering

High-power single-frequency fiber lasers (SFFLs) have widely been applied in various fundamental research areas. However, the increase of intensity-noise with scaling power has prevented the applications that require a high detection sensitivity. Thus, the intensity-noise would be affected by many optical factors in power amplification, such as pumping stability and nonlinear effect. To this end, here we study the influence of stimulated Brillouin scattering (SBS) on the relative intensity-noise (RIN) in SFFL-based master-oscillator power amplifier (MOPA) system. By correlating the power ratio. of the Stokes scattering power to the output signal power to the SBS-induced RIN, we find that, with scaling output power and lengthening the total fiber, an increasing. results in the enhancement as well as the extending effective frequency range of the RIN. Moreover, with the same., different fiber lengths lead to the same amplitude level of the output RIN. Importantly, the resultant SBS-induced RIN has the same trend whether the resonant relaxation oscillation of the seed laser is suppressed. We also perform numerical studies to verify our conclusions. This study can provide the criterion for optimizing the noise-performance of MOPAs and useful insights into the development of high-power SFFLs for coherent detection application.