为了提高采用有限元分析平面光波导热应力的精度和效率, 提出了一种改进平面应变模型。通过将材料的热膨胀系数正交各向异性化, 材料垂直于波导传播方向的热膨胀系数为真实的热膨胀系数, 但沿波导传播方向的热膨胀系数经过适当的变换可满足变形协调和适应平面应变模型, 采用改进的平面应变模型, 计算了平面光波导的热应力。计算结果表明, 与广义平面应变模型相比, 用改进的平面应变模型得到的应力的最大误差只有0.4%, 而计算时间缩短为广义平面应变模型的12.6%, 与平面应变模型相比, 改进平面应变模型的计算时间相等, 而计算精度大幅提高。

In order to improve the accuracy and efficiency of the thermal stress analysis of the planar optical waveguide by the finite element method, an improved plane strain model is presented. In this improved plane strain model, the thermal expansion coefficient of materials is described in orthogonal anisotropic way, and the material’s thermal expansion coefficient in the direction perpendicular to the propagation of the waveguide remains the actual material’s thermal expansion coefficient. However, the thermal expansion coefficient of material along the direction of propagation of the waveguide is changed appropriately to maintain deformation coordination. With the modified material model, the thermal stress of the planar optical waveguide is calculated by the ordinary plane strain model. The calculation results show that the maximum error of the stress obtained by the improved plane strain model is only 0.4% compared with the generalized plane strain model, and the calculation time is reduced to 12.6% of the generalized plane strain model. Compared with the ordinary plane strain model, the calculation precision of the improved plane strain model is greatly improved with almost same calculation time.