Structural characterization of erbium containing glasses by using molecular dynamics simulations

Erbium containing glasses cover an important role in optical communications such as optical amplifiers. It is well know that the concentration of erbium into the glass influences the optical response of the material, therefore in the last years particular attention was devoted to the analysis and characterization of the erbium local distribution in the glass network. The presence of high erbium concentration in the glass is correlated to the formation of Er3+ based clusters and this inhomogeneous distribution of the rare earth ions induces changes in the energy transfer between neighbouring ions leading to the concentration quenching of luminescence, experimentally observed for this class of optical materials. In this communication, the structural evolution occurring in the erbium sites, its modifier role and the changes induced by the alumina addition in the glasses have been extensively studied by using molecular dynamics technique. The effect of alumina on the clustering effect, typical of the glasses containing high erbium concentration, was defined for three main systems characterized by the presence of increased percentage of erbium oxide in the glass formulation.