ABSTRACT
The discovery of photosensitivity in optical fibers has had major role in the development of telecommunication and sensor systems technologies, the effect being used to develop devices for many applications. The construction of a fiber Bragg grating (FBG) is usually based on the photosensitivity property of silica fiber doped with germanium. Photosensitivity means that exposure of ultraviolet (UV) light results in a rise in the refractive index of certain doped glasses. In FBGs have been a growing interest due to their ability in design for wide wavelength-selective range; therefore, they can be used in a variety of applications. For telecommunications, probably the most promising applications have been dispersion compensation and wavelength-selective devices such as filters for wavelength-division multiplexing. Photosensitivity in optical fiber usually refers to the permanent change in the refractive index of the optical fiber core that is induced by exposure to highly UV light radiation.
