L-波段级联结构掺Er光纤放大器的优化设计

在前级Er光纤（EDF）长度和抽运功率确定的前提下，通过改变后级抽运功率，对L波段级联结构掺Er光纤放大器（EDFA）的两级光纤长度的比例进行了优化研究。当前级的抽运功率和光纤长度分别为60mW和5．4m时，通过对后级参数进行优化，小信号增益达到了30．1634dB，同时噪声指数仅为4．078dB。与其它设计方案相比，该方案更具有实用性：首先，可以通过选择适当的后级抽运功率使级联放大器得到足够大的增益；其次，可以充分利用抽运光能量，从而提高抽运利用效率。

Optimal Design of L-band Preamplifier with Cascade Structure

The proportion of erbium-doped fibre(EDF) length of dual-stage L-band EDF amplifier(EDFA) with cascade structure is optimized,which is done by changing pump power of the second stage under the condition that the EDF length and pump power of the first stage is determined.When the pump power and EDF length of the first stage are 60 mW,and 5.4 m,respectively,the small signal gain is 30.163 4 dB and the noise figure is less than 4.078 dB by optimizing the parameters of the second stage.Compared with other methods,enough high gain could be obtained by choosing proper pump power of the second stage,and this method could make good use of pump power to improve the pump efficiency so the method is more useful.