Influences of stimulated Raman scattering on Q-switched fiber lasers

In this work, the influences of stimulated Raman scattering (SRS) on Q-switched fiber lasers are studied experimentally and theoretically. In the experiments, the SRS was investigated in the temporal and spectral domains based on an actively Q-switched ytterbium-doped double-clad fiber laser. In the theory, the dynamic characteristics of SRS in Q-switching processes were analyzed by solving a set of laser rate equations in combination with the SRS. With the aid of numerical simulation, the evolution of Raman pulses together with the laser pulses was traced in the fiber laser cavity. The SRS in Q-switched fiber lasers exhibits a few distinct features from those in high-power continuous-wave fiber lasers. A quantitative analysis of the SRS influences on Q-switched lasers is given in this paper, which is important to the design and optimization of Q-switched fiber lasers.