提出了在计算多模增益光纤有效受激布里渊增益系数时,以优化的高斯模场面积作为光纤有效截面积的方法,并基于光强耦合微分方程,研究了多模增益光纤稳态受激布里渊散射的效果.结果表明,无论是一阶还是二阶受激布里渊散射,随着泵浦功率的增加,残余的泵浦功率都将达到饱和,而Stokes功率都线性增加;二阶Stokes功率相对较弱;光纤的有效长度随泵浦功率的增加逐渐减小.

A method of the core area replaced by the optimum Gaussian mode area was proposed when calculating the effective stimulated Brillouin scattering gain coefficient. Then, the effect of steady-state Stimulated Brillouin Scattering (SBS) in a long multimode gain fiber was studied based on the coupled differential equations on beam intensity. The results show that the residual pumping power becomes saturated, and the Stokes power increases linearly with the launching power for whether the first-order or second-order SBS process. This study also shows that the second-order Stokes power is relatively weaker, and the effective length of the fiber decreases gradually with the increase of the launching power.