Effect of Ce3+(Eu3+) codoping on the spectroscopic properties of Er3+ in bismuth-germanate glass

In order to improve the transition rate from the 4I11/2 level to the 1.53 μm fluorescence emitting 4I13/2 level of Er3+, the Ce3+ and Eu3+ ions were respectively introduced into the Er3+ doped bismuth-germanate glass with a composition of Bi2O3–GeO2–Ga2O3–Na2O. The energy transfer mechanisms between Er3+ and the codopants were discussed based on their energy level diagrams. Though Ce3+ was less effective than Eu3+ on the decrease of the 4I11/2 level lifetime, it hardly influenced the lifetime value of 4I13/2 level. Both the 4I11/2 and 4I13/2 levels were depleted severely at the same time with the codoping of Eu3+. As a result, Er3+/Ce3+ codoping improved the 1.53 μm fluorescence emission intensity, while Er3+/Eu3+ codoping had a deleterious effect on it. The results indicate that the Er3+/Ce3+ is a preferable codoped scheme for bismuth-germanate glass with low phonon energy to obtain an efficient broadband EDFA pumped at 980 nm.