The Site of Er in Phosphate Glasses Studied by K-Edge EXAFS

In the study of Rare Earth (RE) doped glasses for applications in optical amplifiers a key issue is represented by the role of local structure on the fluorescence lifetime τ. In particular clustering of the RE ions leads to a drop of τ and to a degradation of the device performances. K-edge EXAFS is particularly effective in revealing RE-RE coordinations as it permits to access the high k region (k > 10 A-1 where only the RE neighbors contribute to the spectrum. In this contribution we show an application of this experimental method to the study of Er-doped aluminophosphate glasses