Spectroscopic properties of Er3+-doped PbO-Ga2O3-GeO2 glass for optical amplifiers

The spectroscopic properties of Er2O3-doped PbO-Ga2O3-GeO2 glasses were investigated. The measured lifetime and stimulated emission cross-section of the 4I13/2 level were 4.73 ± 0.05 ms and 6.8 × 10−21 cm2, respectively. The measured lifetime and stimulated emission cross-section were 0.31 ± 0.02 ms and 1.9 × 10−21 cm2 for the 4I11/2 level, respectively. The lifetimes of 4I13/2 levels were almost constant up to the Er3+ concentration of ∼1.3 × 1020 cm−3. The constant α(6) for energy migration of the 4I13/2 level was considerably higher than that of the 4I11/2 level. On the other hand, the coefficient of cooperative upconversion for the 4I13/2 level was 104 times smaller than that for the 4I11/2 level at the concentration of 2.57 × 1020 cm−3. These results suggest that the contribution of the migration-accelerated energy transfer among Er3+ ions to the non-radiative transition from the 4I13/2 level is larger than that from the 4I11/2 level, whereas the non-radiative transition from the 4I11/2 level is mainly due to the cooperative upconversion effect via 4I11/2:4I11/2 → 4 F7/2:4I15/2 process. The obtained results also indicate that the PbO-Ga2O3-GeO2 glass is a good candidate for short optical fiber amplifiers.