利用Giles模型对L波段掺铒光纤放大器小信号增益特性进行了数值模拟 ,模拟结果表明最佳铒纤长度并不是一定值 ,它随输入信号波长的不同而改变 ,较短的波长对应较短的光纤长度 ;在数值模拟、分析的基础上 ,分别采用 7m和 9m的L波段铒光纤构成长波段掺铒光纤放大器 ,通过实验测量 ,分析比较了它们的自发辐射谱以及增益和噪声指数 ,得到了光纤长度对L波段增益谱、噪声指数和自发辐射谱的影响规律 ;最后 ,辅以C波段掺铒光纤放大器加以分析 ,指出了适合于放大L波段信号的最佳自发辐射谱型。 The Giles model is used to simulate the small-signal gain of L-band erbium-doped fiber amplifier. The simulation results show that the optimum erbium fiber length is not constant, which varies with the input signal wavelength. The shorter wavelength corresponds to a shorter Based on the numerical simulation and analysis, the long-wavelength erbium-doped fiber amplifier is constructed by using L-band erbium fiber of 7m and 9m respectively. The measured spontaneous emission spectrum and gain and noise figure of the fiber are analyzed and compared. Fiber length on L-band gain spectrum, noise index and spontaneous emission spectrum; Finally, assisted by C-band erbium-doped fiber amplifier to analyze, pointed out suitable for amplification of the L-band signal optimum spontaneous emission spectrum.