Measurement of thermal binding energy of photodarkening-induced color centers in ytterbium-doped silica fibers

The authors report on thermal bleaching measurements of photodarkening-induced color centers in ytterbium-doped silica fibers. The authors make use of the similarity between UV and photodarkening-induced defects and apply a model, developed to describe and predict the performance of thermal decay of UV-induced fiber Bragg gratings, to study the thermal binding energy associated with photodarkening-induced color centers. This model assumes a broad distribution of trap sites, with the rate of thermal depopulation being an activated function of the trap depth.