Photosensitivity of oxygen deficient type bulk silica and fibers

With the development of fiber gratings, the investigations of optical phenomena induced by UV-laser irradiation such as the photosensitivity of silica-based glasses and optical fibers have been areas of active research. The severe conditions implicit in the fiber fabrication process including high melting temperatures, shear stress, neck down and rapid quenching were found to generate structural defects that are different from those present in bulk rods. Subsequent exposure of the fibers to UV-laser radiation therefore results in the modified photosensitivity of the drawn fibers. In this study, the effects of UV excimer laser (KrF) irradiation on the optical properties of silica fibers are compared to bulk rods from which they have been drawn.