Optical Fiber Bragg Grating in self-focusing control and pH sensor

The transmission of light through optical fibers continues to be a major focus for researchers. This study centers on optical fiber Bragg grating (FBG) constituted of cladding and core in two configurations, consequently, for two applications. These two systems contain a Bragg grating placed in the core center. The first optical fiber has FBG within the center of the core and its response is studied through a laser beam with a Gaussian shape propagating along the core. Since the fiber core has an intensity-dependent refractive index, the highest value will be reached at the center of fibers focusing the beam. This phenomenon is known as self-focusing. The integrated FBG aims to spatially influence the self-focusing effect. FBG in the second fiber optic sensor is combined with a pH-responsive polymer coating to monitor the pH of examined solutions. These two systems provide promising sensors for pH, strain, and temperature monitoring. The optical sensors arrangements are modeled through the Wave Optics Module in Comsol Multiphysics environment, which is based on the Finite Element Method (FEM) solver.