In this work, we describe a theoretical approach for combined thermal, mechanical and optical simulation and analysis of planar polymer waveguides. We consider a finite element approach for thermal and stress/deformation simulation. Also, a Crank-Nicholson finite difference beam propagation method (CN-BPM) is implemented to perform the optical simulation. The results of the finite element (thermo-mechanical) analysis are coupled with the CN-BPM results to carry out the optical simulation of poly(methyl methacrylate) (PMMA) waveguides as function of temperature. For thermal simulation, a model was designed where a polysilicon microheater was added to the upper cladding of the PMMA waveguides to vary the temperature between 20 C and 200 C. Thus, the impact of the induced temperature gradients on the refractive index modulation of the PMMA waveguides and the corresponding change in numerical aperture are obtained. In addition, the temperature gradients influence the beam intensity profiles and the movement of the primary eyes within the optical waveguides, thus, impacting the optical properties. Furthermore, the thermally induced mechanical stress and deformation were calculated for transverse and axial directions. In the next step, validation of the model by systematic experimental studies will be performed. In general, our approach provides a toolbox for more comprehensive multi-physics theoretical analysis of polymer-optical waveguides which, in future, can be extended to more complex and functional structures as required for flexible sensor networks, as example.

在这项工作中，我们描述了一种用于平面聚合物波导的热，机械和光学组合仿真和分析的理论方法。我们考虑一种用于热和应力/变形模拟的有限元方法。而且，实施了Crank-Nicholson有限差分光束传播方法（CN-BPM）以执行光学仿真。将有限元（热机械）分析的结果与CN-BPM结果相结合，以进行聚甲基丙烯酸甲酯（PMMA）波导随温度变化的光学仿真。对于热仿真，设计了一个模型，其中在PMMA波导的上包层中添加了一个多晶硅微加热器，以在20°C至200°C之间改变温度。获得了诱导温度梯度对PMMA波导折射率调制的影响以及数值孔径的相应变化。另外，温度梯度影响光束强度分布和光波导内的主眼运动，从而影响光学性能。此外，计算了横向和轴向方向的热机械应力和变形。在下一步中，将通过系统的实验研究对模型进行验证。总的来说，我们的方法为聚合物光波导的更全面的多物理场理论分析提供了一个工具箱，例如，将来可以扩展到柔性传感器网络所需的更复杂和功能更强的结构。