Optical fiber radiation damage measurements

The results of studies of changes in the spectroscopic properties of commercial fibers are reported. Analysis of the attenuation spectra of various fibers have confirmed the expected different behavior of Ge-doped and pure silica fibers. However, differences in spectra of fibers made nominally from the same materials but using different processes were also observed. It is therefore concluded that the manufacturing process as well as doping determine the relative abundance of Type I and II color-center defects. The Raman spectra of the fibers were also obtained and analyzed. A strong resonant fluorescence at 650 nm, thought to be due to Type II color-centers, was observed in certain fibers. In general the changes in Raman spectra followed the theoretical expectation, however, the differences between fibers could not be entirely attributed to the doping levels. Again the manufacturing process and the subsequent treatment of fibers is thought to be partially responsible.