对级连结构的L波段EDFA进行了优化设计.首先用加拿大Optiwave的OptiAmplifier4.0数值模拟了在其他条件确定情况下两级光纤长度比例变化对放大器性能的影响,在优化光纤长度比例的基础上,为了得到更宽的L-EDFA的本征平坦增益谱,进一步优化了前后级泵浦功率.在上述条件下利用42 m的铒纤得到实验结果为:ASE谱3 dB带宽1566.84～1606.80 nm(40 nm).在L波段(1570～1605 nm),小信号平均增益约为25 dB,增益不平坦度为±1 dB,噪声指数约为5 dB.

The dual-stage L-band EDFA is optimized. At first, we make a simulation about the effect to the L-band EDFA by change of the proportion of EDF length of each stage by OptiAmplifier4.0 with other factors unchanged. Then we make a further optimization to the pump power of each stage to obtain the intrinsic flat gain spectrum as wide as possible. Based on that a experiment with a 42 meter long EDF is made, with the outcomings as follows: the ASE spectrum is from 1566.84 nm to 1606.80 nm within 3dB bandwidth,which is about 40nm,Within the L_band spectrum,the small signal gain is about 25dB,Noise figure is about 5dB.