为了简单、快捷地模拟掺镱双包层光纤放大器的脉冲放大特性，采用有限元软件FEMLAB模拟掺Yb³⁺双包层光纤放大器的脉冲放大特性。用与快速傅里叶法模拟Yb³⁺光纤放大器脉冲放大特性相同的参量计算了在915nm前向抽运下，光纤放大器中的上能级粒子数，抽运光和放大自发辐射在光纤中的稳态分布，以及高斯脉冲和方波脉冲的输出、能量及增益特性，得到的与快速傅里叶法模拟的一致的粒子分布图等特征图，而且比快速傅里叶法得到更多和更准确的结果。结果表明，应用FEMLAB只需根据掺Yb³⁺光纤放大器的方程组，可以方便、快捷地确定参数进行数值模拟，对掺镱光纤放大器的系统设计和参量优化具有很好的参考价值。

The main purpose of this paper is to present the simple and fast method for simulating the characteristics of pulse amplification in ytterbium-doped double-clad fiber amplifiers with finite elements model FEMLAB package. The upper-level population distribution in the fiber,the pump power and the amplified spontaneous emission with 915nm forward pumping were studied by using the same parameters with the finite elements model fast Fourier transform. The transient output power,stored energy and gain of Gaussian pulse and square pulse were simulated. These results are in good agreement with those obtained according to fast Fourier transform. Furthermore,these results are more exact. The results show this method is convenient and fast. This method will offer valuable reference in design and parameter optimization of ytterbium-doped fiber amplifiers.