Er3+掺杂的Bi2O3-B2O3-SiO2玻璃的光谱性质

测试了Bi₂O₃-B₂O₃-SiO₂玻璃中的Er³⁺离子的吸收光谱、发射光谱、⁴I_13/2的荧光寿命、拉曼光谱,及OH^-的傅里叶红外吸收光谱。应用Judd-Ofelt理论计算了该玻璃中的Er³⁺离子的J-O参数、振子强度、⁴I_13/2能级的寿命,从而利用测得的⁴I_13/2的荧光寿命得出了⁴I_13/2能级的量子效率(15%)。由于较低量子效率可能与OH^-有关,所以计算了玻璃中的OH^-浓度,发现其浓度较高(1.66×10¹⁹cm^-1,相当于Er³⁺浓度的3倍)。应用McCumber理论和四能级模型计算了Er³⁺离子的受激发射截面和荧光发射光谱的半峰全宽,结果与通过吸收光谱计算所得基本吻合。根据透射率和折射率的关系计算了折射率,发现和测量值相差很大,说明有较大的散射,通过拉曼光谱和显微镜测试,认为是玻璃中的微小气泡造成的。

Spectroscopic Properties of Er3+ Doped Bi2O3-B2O3-SiO2 Glasses

Erbium-doped fiber amplifiers(EDFAs) with wide and flat gain spectra in telecommunication windows are the key issues for dense wavelength division multiplexing(DWDM) optical network systems.How-(ever),the traditional commercialized EDFAs are made of SiO₂-based material in which Er³⁺ ions show a narrow (emission) bandwidth for the ⁴I_13/2→⁴I_15/2 transition.Many methods have been investigated to broaden and flatten the gain spectra of the traditional EDFAs in order to meet the capacity demand.Recently,tellurite glasses have received considerable attention in EDFAs for the broad bandwidth of over 70 nm,which meets the transmission capacity of DWDM systems.Nevertheless,the bad thermal stability and the high up-conversion become the(unsolvable) obstacle.Compared to tellurite,borate is a better glass-former compound and has higher(stability),larger phonon energy and broad bandwidth.We prepared Er³⁺ doped Bi₂O₃-B₂O₃-SiO₂ glasses according to the following molar composition: 40% Bi₂O₃,20% B₂O₃,40% SiO₂,and 3.0% Er₂O₃ is added to dope the glasses.The absorption spectra for Er³⁺ and OH^-group,emission spectra and luminous decay for the transition ⁴I_13/2→⁴I_15/2 were measured.Accor-(ding) to the standard J-O procedure the intensity parameters for the Er³⁺ in the prepared glass were obtained.The concentration of OH^-group and inner quantum efficiency for ⁴I_13/2 level were estimated.It is validated that the lower quantum efficiency is caused by the higher content of OH^-group,about 3 times of Er³⁺(content.) On the base of McCumber theory,the stimulated emission cross section for the ⁴I_13/2 level was derived and found to be in better agreement with the results calculated by using the emission spectra.We draw a conclusion that it is essential for the borate used in EDFAs to decrease the higher content of OH^-group despite of higher stability,larger phonon energy and broad bandwidth.