根据聚合物脊型波导的结构特点，利用有效折射率法求出其横向折射率分布，将三维传播转化为二维传播，并从标量波动方程出发，在傍轴近似的情况下，采用Crank-Nicholson差分格式，得到了泰勒级数展开法基本计算格式，并对算法进行了适当优化；通过对Mach-Zehnder光波导TM模的模拟，分析了各种参数对损耗的影响。结果表明：泰勒级数展开法具有精度高、稳定性好、算法简单、易于编程等优点，是一种比较理想的光波导数值分析方法，可为聚合物电光调制器的设计制作提供理论参考。

Mach-Zehnder waveguide is an important part in integrated optics. The transverse distribution of refractive index of polymeric ridge waveguide was calculated with the effective index method (EIM) and 3-D propagation was converted into 2-D propagation according to the structural characteristics of the polymeric ridge waveguide. Based on paraaxial scalar equation, using CrankNicholson scheme, the basic calculation scheme of Taylor series expansion method was obtained and optimized. By simulating the TM mode of a real Mach-Zehnder waveguide, the influence of various parameters on the loss was analyzed. The results show that this method is accurate, stable and easy to program.