Effect of Bi2O3 on spectroscopic properties and energy transfer in Yb3+-Er3+-co-doped bismuth borate glasses for 1.5 μm optical amplifiers

In this paper, the effect of Bi2O3 on the optical absorption and emission, energy transfer, and gain property of Yb3+-Er3+-co-doped bismuth borate glasses has been investigated. An increase of the emission cross-section and fluorescence lifetime of Er3+ ions around 1.5 μm with Bi2O3 content was shown. The increase of Bi2O3 content is also beneficial to obtaining a large absorption cross-section at 980 nm and increasing the energy transfer from Yb3+ to Er3+. Furthermore, in the 45Bi2O3-55B2O3 glass, gain curve is almost flat in the range from 1.53 to 1.60 μm. The results indicate that the Yb3+-Er3+-co-doped bismuth borate glasses have good prospect as a candidate of gain medium for 1.5 μm broadband amplifier.