Photodarkening measurements in Yb-doped silica fibers in correlation with cooperative luminescence

In this study, detailed investigation of photodarkening in Yb - doped aluminosilicate fibers is reported. The cooperative luminescence loss influenced by photodarkening is measured simultaneously with 633 nm probe loss. The quadratic dependence of photodarkening and cooperative luminescence versus dopant concentration was observed. The results indicated lower cooperative luminescence loss at 513 nm than expected and provided new pieces of information to the photodarkening mechanism description.