Numerical analysis of Raman effects in high power fiber lasers

Based on the numerical simulation method for solving the steady-state rate equations that describe the pump,laser and Stokes waves,the dependence of Raman effects on the parameter of high power Yb3+-doped double-clad fiber laser was investigated.The distribution of laser power and Stokes power along the fiber,and the relation between the threshold pump power for the generation of the stimulated Raman scattering(SRS) and the parameter of fiber laser were obtained.Numerical results show that the threshold pump power for the generation of SRS can be improved,and the Raman effects can be effectively suppressed by using large mode area fiber,shortening the cavity length,reducing the emission cross-section of Yb3+ at the Stokes wavelength and adopting a longer lasing wavelength.