Stress-Optical Effects with Generalized Plane Strain
Application ID: 190
Planar photonic waveguides in silica (SiO2) have great potential for use in wavelength routing applications. The major problem with this type of waveguide is birefringence. Anisotropic refractive indices result in fundamental mode splitting and pulse broadening. The goal is to minimize birefringence effects by adapting materials and manufacturing processes. One source of birefringence is the use of a silicon (Si) wafer as the substrate onto which the waveguide structure is deposited.
After annealing at high temperatures, a mismatch in thermal expansion between the silica and silicon layers results in thermally induced stresses in the structure at the operating temperature (typically room temperature).