Elasto–optical behavior model of a step-index fiber under localized pressure

The intensity attenuation of a step-index optical fiber under localized pressure is investigated using the elasto–optical theory and the principles of geometrical optics. A model with a Gaussian variation of the refractive index in the axial direction is used to evaluate the effect of applied pressure on the external coating of the fiber. The results are compared with experimental measurements obtained using a prototype of an optical fiber pressure sensor.

► The intensity attenuation of a step-index fiber under localized pressure is evaluated.
► The model is based in the elasto–optical theory and the geometrical optics.
► The refractive index is modeled as a Gaussian function of the position and stress.
► Numerical solution and experimental data of a pressure sensor prototype are compared.
► The model describes some effects of external agent on the light transmission loss.