Spectroscopic properties of Er:I13/2 level in Bi2O3-B2O3-GeO2-Na2O glasses

Spectroscopic properties of Er3+:4I13/2 - > 4I15/2 transitions in erbium-doped bismuth-borate glasses with composition of 45Bi2O3-35B2O3-10GeO2-10Na2O were investigated. The results show that the fluorescence intensity reveals a nonexponential decaying behavior for glasses with low Er3+-doped concentration. It is ascribed to the energy transfer from Er3+ to OH- groups, and the energy-transfer microparameter CEr-OH is about 33.1 X 10-40 cm6 s-1 in Er2O3-doped content of 0.1 mol% glass. Whereas an exponential behavior is dominant for glasses with high Er3+-doped case. Nonradiative decay in the latter is mainly originated from the energy migration among Er3+ ions, and this energy migration is also responsible for the concentration quenching of 1.53 mum fluorescence emission. The interaction microparameter CEr-Er for the migration among Er3+ ions was calculated to be an average of 43.9 X 10-40 cm6 s-1. Meanwhile, the radiation trapping of Er3+ leads to the effective emission width broadening from 66.3 to 82.5 nm with Er2O3 doped content increased from 0.1 to 3.0 mol%.