中文摘要：

利用Er^3＋离子四能级结构速率方程组和光功率传输方程组，数值模拟了铋基掺铒光纤放大器（EDFA）的增益及噪声特性，模拟结果与实验报道结果取得了很好的一致。同时，详尽地分析了增益及噪声特性与光纤长度、泵浦功率和输入信号功率的关系，优化了放大器的性能，从理论上得出一个20dB增益带宽达76nm、噪声系数接近4dB的铋基EDFA。研究表明了铋基掺铒光纤放大器适合用作于现代DWDM系统中C＋L波段的光纤放大器。

英文摘要：

Based on the rate equations and light propagation equations of Er^3＋ ions four energy level transition systems, the numerical simulations on gain and noise figure of Erbium-doped Bismuth fiber amplifier were researched, and the results showed a good agreement with the published experimental results. Furthermore, gain and noise figure changing with the activated length of fiber, signal input power and pumping power were presented in detail. The theoretical study shows that the bandwidth is 76nm for 20dB gain and the noise figure is nearly 4dB when the input condition is optimum. The research shows that Erbium-doped Bismuth-based Optical Fiber Amplifier （EDFA） is suitable for C＋L band fiber amnlifiers in nresent dense wavelength division multinlexing（DWDM） system.