为了获得更精确的光栅衍射效率, 采用严格耦合波理论建立体布喇格光栅衍射机理模型, 分析了运用严格耦合波理论实现体光栅的衍射效率计算, 并利用正交Legendre多项式展开法求解耦合波方程,取得了体布喇格光栅衍射效率稳定的数值解, 得到的仿真结果符合理论计算。结果表明，相对于矩阵法，该算法具有更好的收敛速率，且比Kogelnik耦合波理论解法更精确。

In order to obtain the accurate diffraction efficiency of gratings, the diffraction mechanism of volume Bragg gratings was established and the diffraction efficiency was calculated with the rigorous coupled-wave method. The first-order coupled Maxwell’s equations was solved in terms of Legendre polynomials, and the diffraction efficiency of volume Bragg gratings was obtained. The simulation results were consistent with theoretical calculation results. This method converges faster than the matrix method, and is more precise than the Kogelnik coupling wave theory.