Underlying mechanisms, applications, and limitations of chemical composition gratings in silica based fibers

This paper reviews the manufacturing procedure and properties of high-temperature stable chemical composition gratings in silica based optical fibers. Chemical composition gratings are formed by a periodic change in the distribution of dopants by UV exposure and thermal processing, which results in differential diffusion. This is attained through interaction between dopants in the fiber and UV induced hydroxyl groups. The formation of fluorine and oxygen modulated chemical composition gratings is presented and their applications and limitations are discussed.