基于受激布里渊散射Langevin噪声模型，通过近似的三波耦合方程组，采用了时域有限差分法，对光纤中受激布里渊散射过程进行数值模拟计算。对长度为10 km，折射率为1.5132的单模光纤，分析了50 μs内光纤中的光场和声波场的时间和空间变化特性和散射光的功率变化特性。数值模拟中，在一定的抽运入射光作用下，把Stokes光作为起振光入射到光纤的另外一端，发现起振光的存在与否会影响到抽运光场、散射光场和声波场的时间空间振幅变化，并且得出存在Stokes光时散射光的功率随时间趋于饱和以及没有Stokes光时散射光功率随时间的近似线性变化。

Through the approximate three- wave- coupling equations, based on Langevin noise model of the stimulated Brillouin scattering, the stimulated Brillouin scattering process in optical fiber is numerically simulated using the finite difference time domain method. As for the single-mode fiber of 10 km long and with the refractive index of 1.5132, the characteristics of the optical field and the acoustic field of the temporal and spatial variation and the power variation of scattering light within 50 ms are analyzed. In the numerical simulation, under the function of pump beam and with Stokes light as the incident vibration light into the other end of the optical fiber, it is found that whether the polarized light exists or not will affect the amplitude of the temporal and spatial variation of the pump light, scattering light field and acoustic field, and it is obtained that the scattering light power tends toward saturation with time when the Stokes light exists and the scattering light power shows nearly linear variation with time when no Stokes light exists.