Ge-doped silica fibers: modeling of photosensitivity

Abstract

This work proposes a complete photosensitive model based on the color center approach for Ge-doped silica fibers. It permits accurately to predict the refractive index growing dynamic in the Fiber Bragg Gratings (FBG) writing process. The model is based on the study and mathematical modeling of the physical processes that takes place when the fiber is irradiated with a high power UV light source. A bibliographic review and discussion is presented, and an initial model is established. As this initial model did not reproduce the experimental results reported in the bibliography, we considered that there were some other processes still not considered. We have introduced important modifications, which are based on interpretation of physically viable and probable photochemical reactions that take place in the FBG writing process. The mathematical equations for the model are introduced and simulation results matching experimental data are presented in order to validate our model.