利用变分有效折射率法计算了TE基模和高阶模的光场分布，计算结果表明，该方法计算量小，精度高，为聚合物集成光电子器件中脊形光波导的理论分析与优化设计提供了简单高效的途径。利用有限差分束传播法对Mach-Zehnder波导的传播及损耗特性进行了理论分析，得到了不同Y分支角、波导宽度、波导间距时波导传输功率与距离的关系，优化得到的结构参数为：Y分支角1.1°，脊宽5 μｍ，波导间距20 μｍ。

Polymeric Mach-Zehnder rib waveguide is an important component in polymeric integrated electro-optic devices. A new technique is used for computing the optical field distribution of the fundamental and higher order modes for TE modes of a polymeric Mach-Zehnder rib waveguide. The technique is based on the combination of the effective index method and the variational method，and has advantages such as high precision, low calculation complexity and high efficiency, which can provide theoretical reference and optimization method for the fabrication of polymeric electro-optic devices. Important parameters of the waveguide are discussed and their relations with the optical power propagation and loss characteristics are investigated by using the finite difference beam propagation method. The optimized structure parameters are obtained: Y-junction angle is 1.1°, rib width is 5 μｍ, separation gap is 20 μｍ.