为了探讨超短光脉冲在分布式光纤放大器中的传输放大特性及影响因素, 建立了光脉冲在光纤放大器中的基本传输方程, 以掺镱光纤放大器为例, 采用分步傅里叶变换法对放大器中光脉冲的演变进行了模拟, 讨论了初始啁啾和增益色散的影响。结果表明, 当光脉冲在分布式光纤放大器中传输时, 光纤的色散、非线性效应均会影响脉冲的形状和频谱, 光脉冲初始啁啾也会对脉冲的传输状态产生影响; 对于宽频谱光脉冲, 增益色散相当于一种损耗机制, 应该考虑其影响。相关结果对光纤放大器的系统设计和优化具有一定的参考价值。

In order to discuss the propagation and amplification characteristics of ultrashort optical pulse in distributed fiber amplifiers and the influencing factors, its basic propagation equation was established. Taking an ytterbium-doped fiber amplifier as example, the evolution of optical pulse in the amplifier was simulated by means of split-step Fourier transform method. Then the effect of initial chirp and gain dispersion were discussed. The results show that when the optical pulse propagates in a distributed optical fiber amplifier, dispersion and nonlinear effect of the fiber will affect pulse profile and frequency spectrum, and initial chirp also influence the propagation state of optical pulse. For wide-spectrum optical pulse, gain dispersion is equivalent to a loss mechanism, so its influence should be considered. Relevant results have certain reference value to the system design and optimization of optical fiber amplifiers.