Effect of Er~(3+) Ion Concentration on the Fluorescence Properties of Tellurite Glass

Fluorescence properties of Er~(3+):~4I_(13/2)→~4I_(15/2)transition were measured in a tellurite glass.The fluorescence spectra,fluorescence intensities and lifetimes were investigated as a function of erbium ion concentration.It is found that there are intense radiation trapping and concentration quenching effect in erbium-doped tellurite glasses.With the increase of erbium ion concentration, fluorescence spectrum broadens significantly and its main emission peak shifts from 1532nm to 1556nm as a result of the changed relative intensity of each spectral component caused by radiation trapping. Fluorescence intensity decreases strongly with higher erbium ion concentration due to concentration quenching effect caused by cooperative upconversion among Er~(3+)ions.Also,radiation trapping and concentration quenching cause fluorescence lifetime increase at first and then decrease rapidly with the increase of Er~(3+)concentration.