This book focuses on the detailed investigation of stress-induced birefringence in polymer optical waveguides and demonstrates an approach for the potential design of polarization-insensitive waveguide devices considering such stress-effects. To estimate the stresses accurately, it presents a process-modeling framework in the Finite Element analysis, which can incorporate important stress build-up processes, such as polymerization shrinkage, stress relaxation, and etching, over the entire history of the waveguide fabrication process. It also presents the characterization of the stress-optic and thermo-optic coefficients of polymers in thin film waveguide. Being generic in nature, the described approach enables the optimized design of various integrated optical devices from the standpoint of material systems, waveguide geometry, and process parameters. This book is expected to lay the groundwork for the researchers on the management of stress related problems in integrated optical devices and photonic packaging.