Modeling Strain Effects in a Ridge Waveguide
Application Notes
This application note shows how to use RSoft’s Multi-Physics Utility to model strain effects in a silicon ridge waveguide. Strain can change the refractive index of materials through the elasto-optic effect, which affects the optical performance of devices such as fiber sensors, amplifiers and waveguides exposed to thermal changes.
In this example, we analyze a silicon ridge waveguide buried in silicon dioxide (SiO₂). The structure has a 2 μm × 2 μm core and a 1 μm thick cladding layer. The Multi-Physics Utility calculates the strain profile caused by differences in thermal expansion and the resulting change in refractive index. We then simulate the optical mode with and without strain.
The results show that strain changes the effective index of the fundamental mode by about 0.0016. This example highlights how strain can impact waveguide performance and how the Multi-Physics Utility can be used to include these effects in optical simulations with tools like BeamPROP, FullWAVE and FemSIM.