Stimulated Raman scattering and thermal effect in high power double clad fiber laser

Stimulated Raman scattering(SRS) and thermal effect can limit the power scaling of fiber laser. According to rate equations and heat conduction equations, SRS and thermal effect in high power Yb3+ doped double clad fiber laser are studied for two-end pumping and distributed pumping. The power distribution of pump, laser and Stokes in the fiber, the output characteristic of fiber laser, and temperature distribution in the fiber are obtained. The results show that the slope efficiency and maximum output power for distributed pumping are slightly less than the ones for two-end pumping, but the temperature distribution is decreased effectively for distributed pumping. The results are very useful for designing high power fiber lasers.