Radial distribution of attenuation in gamma-irradiated single-mode optical fibers

In this letter, a method to determine the radial distribution of attenuation in single-mode optical fibers is proposed. This method is based on guided mode power and loss measurements for different fiber packaging. The most accurate radial attenuation distribution is calculated from experimental results. This approach allows localizing the absorbing or scattering defects along the radial cross section of fibers. As an example, a γ-irradiated germanosilicate fiber is studied at three different wavelengths. Through correlation with fiber chemical analysis, the contributions of each dopant to the permanent radiation-induced losses can be identified and quantified. At 980 nm, phosphorus-related color centers are the origin of induced losses, whereas for shorter wavelengths the influence of germanium-related color centers on fiber behavior becomes dominant