实验制备了Er3+掺杂质量分数为1%的Ga5Ge20Sb10S65硫系玻璃，测试了其折射率、吸收光谱和荧光光谱，利用Judd-Ofelt和Futchbauer-Ladenburg理论计算了Er3+离子的自发辐射几率、吸收截面和受激发射截面等光谱参数。在综合考虑Er3+离子的交叉弛豫、能量上转换和激发态吸收效应的基础上，应用四能级粒子数速率光功率传输方程模型，模拟计算了Er3+掺杂Ga5Ge20Sb10S65硫系玻璃光纤的中红外2.74 μm波段的增益特性。结果显示，Er3+掺杂硫系玻璃光纤在2.74 μm中红外波段具有较高的信号增益和较宽的增益谱，最大增益值和20 dB增益带宽分别超过了40 dB和200 nm，表明其是可用于中红外2.74 μm波段宽带放大的理想增益介质。

The Er3+ doped (the mass fraction is 1%) Ga5Ge20Sb10S65 chalcogenide glasses are fabricated and the refractive index, absorption spectrum and emission spectra are measured. The spontaneous emission probability, absorption cross-section and emission cross-section are calculated using the theories of Judd-Ofelt and the Futchbauer-Ladenburg equation. Based on the rate equations and light propagation equations, the numerical simulations on mid-infrared gain characteristics for the Er3+ doped Ga5Ge20Sb10S65 chalcogenide glass fiber are calculated. Effects of energy transfer between Er3+ levels due to cross-relaxation, cooperative up-conversion and excited state absorption are considered in simulation. The results show that the Er3+ doped Ga5Ge20Sb10S65 chalcogenide glass fiber has a bigger signal mid-infrared gain and wider mid-infrared gain spectrum, and its maximum signal gain and gain width at 20 dB exceeds 40 dB and 200 nm, respectively. The results indicate that the Er3+ doped Ga5Ge20Sb10S65 chalcogenide glass is a better gain medium which can be applied to broadband amplifiers in mid-infrared.