Modeling of FBG Moisture Sensor in COMSOL

Flexibility of COMSOL multiphysics simulation tool makes it possible to estimate the behavior of the Fiber Bragg Grating (FBG) moisture sensor, analyzes mechanical deformation of FBG exposed to hygroscopic polymers and ultimately evaluate electric field strength of propagating light in FBG as a function of geometry deformation. The 2D Moisture sensor model includes Solid Mechanics interface of the Structural Mechanics Module to analyze the deformation of FBG and Electromagnetic Waves interface of Wave Optic Module to analyze wave propagation in the FBG. Light propagation and reflecting wavelength are simulated based on Snell's and Fresnel's laws and none of the Brag equations and expressions is predefined in the model.