Effects of UV exposure on the attenuation of silica optical fibers

The influence of fiber processing parameters on the ultraviolet (UV)-visible properties of optical fibers and hence their suitability for applications in this wavelength region was investigated. The effect of fiber draw conditions, which include fiber diameter, fiber speed, and in-line UV radiation exposure, were determined for depressed-index glass-clad synthetic-silica-core optical fibers. Core materials containing 1000 p.p.m. and 5.0 p.p.m. [OH] were evaluated for attenuation in the 200-nm to 900-nm wavelength region. Three predominant absorption bands centered at approximately 255 nm, 325 nm, and 630 nm were evident in these materials and dictate their use in the encompassing spectral region. The UV radiation dose applied to the fibers during manufacture was found to interact directly with the bands at 255 nm and 630 nm