Influence of structural parameters of high-power fiber lasers on stimulated Raman scattering and the suppression methods

In high-power fiber lasers, stimulated Raman scattering (SRS) is a major factor limiting its power increase. In order to analyze the influence of the SRS effect on high-power fiber lasers, based on the traditional SRS model, we propose a theoretical model of multimode fiber lasers and fiber amplifiers containing the SRS effect. Then, the theoretical model is used to analyze the influence of various structural parameters of the fiber laser on the SRS effect. According to the simulation analysis results, we constructed a fiber laser system based on a master oscillator power amplifier configuration to carry out verification experiments for various structural parameters. The experimental results show that shortening the length of the gain fiber and the transmitting fiber, choosing a signal light of longer wavelength, and increasing the fiber core diameter can suppress the influence of the SRS effect on the fiber laser. And we apply the analysis results to 3 kW fiber laser system, and successfully achieve the suppression of SRS effect in the highpower fiber laser.