Influence of the P2O5/Al2O3 co-doping on the local environment of erbium ions and on the 1.5 micron quantum efficiency of Er3+borosilicate glasses

In this paper, the absorption properties of Er3+ doped borosilicate glasses with various P2O5 and Al2O3 content are measured for different silica concentrations. The Judd–Ofelt parameters (X2, X4 and X6) have been calculated in order to investigate the local environment of the rare-earth cations. The compositional changes of X2 and X6 are attributed to changes in the bonding between Er3+ and surrounding ligand groups due to structural modifications occurring with the introduction of P2O5 and Al2O3. The luminescence quantum efficiency of the 4I13/2-4I15/2 transition slightly increases with the addition of P2O5 whereas it decreases with the progressive replacement of P2O5 by Al2O3.We noticed that it also increases when the silica content is higher.