为克服碲酸盐玻璃中Er^3+的^4I11/2-^4I13/2无辐射速率较小,不利于980nm激光泵浦下实现1.5μm光放大的缺点,在TeO2-WO3-Li2O玻璃中引入了P2O5组分。考察P2O5摩尔分数对Er^3+的1.5μm红外发射、红绿光上转换发光及^4I13/2能级寿命的影响。利用J-O理论对不同P2O5摩尔分数玻璃样品的吸收光谱进行分析,得到各能级辐射跃迁几率,计算了Er^3+在样品中^4I13/2能级辐射跃迁寿命。重点研究了不同样品中Er^3+的^4I11/2-^4I13/2无辐射跃迁速率随P2O5摩尔分数的变化,可以看出在含6%P2O5玻璃中Er^3+的^4I11/2-^4I13/2无辐射跃迁速率约为不含P2O5玻璃中的3.5倍,同时1.5μm红外发射效率略有提高,另外红绿光上转换发射得到了抑制。因此,含P2O5的铒掺杂碲钨酸盐玻璃更有利于在980nm激光泵浦下实现1.5μm光放大。
In recent years, Er^3+ -doped glasses with a broad 1. 5 μm emission band originating from ^4I13/2 -^4 I15/2 transition of Er^3+ have been extensively investigated for use in erbium-doped fiber amplifiers (EDFA). Among the reported materials, Er^3+-doped telluride glasses exhibited a wide 1.5 μm emission band and a large stimulated emission section and high 1.5 μm emission efficiency. However, as a host for EDFA, telluride glass has some major drawbacks. One of them is the phonon energy of the glass is about 770 cm ^-1, which leads to the ^4I11/2-^4I13/2 nonradiative relaxation rate too slow to allow efficient pumping at 980 nm. To overcome this drawback, S. Shen et al. added WO3, with vibronic energy of W-O bond of 920 cm ^- 1 , into the glass to form tungsten-tellurite glasses. This composition modification increased the nonradiative relaxation rate of the ^4I11/2-^4I13/2 transition and made improvement of population feeding efficiency of ^4I13/2 from the ^4I11/2 level pumped at 980 nm. In this absorption and upconversion paper, P2O5 was introduced into Er^3+ spectra of the glasses are studied. It -doped tungsten-tellurite glasses. Emission, is observed that the nonradiative relaxation rate of ^4I11/2-^4I13/2 transitions and the 1.5 μm emission efficiency increases with the increase of P2O5 content, while, the upconversion luminescence was suppressed. The nonradiative relaxation rate of ^4I11/2-^4I13/2 transition in a glass with 6% P2O5 is about 3.5 times greater than that without P2O5. The present results indicate that telluride glasses with P2O5 addition may be a promising candidate medium for broadband erbium-doped fiber amplifiers with good performance under the pumping of 980 nm.