利用一组耦合方程,在理论上推导出了双抽运、三段光纤级联结构的参量放大器的增益表达式。研究表明在双抽运情况下,光纤参量放大器(FOPA)的增益随光纤长度、抽运光功率的增加而变大;同时,增益的大小和平坦性能也受到光纤色散特性的影响,从反常色散区到正常色散区,增益带宽逐渐变小,增益不平坦性有一定的改善;在二阶色散系数不变的情况下,光纤参量放大器增益带宽随四阶色散数的增加而减小。采用多段光纤级联结构,可以均衡光纤参量放大器增益的不平坦性。

By the use of a set of coupled equations, the gain expression of two-pump fiber optical parametric amplifier (FOPA) with three-section nonlinear fibers is deduced theoretically. It is indicated that the parametric gain has a relationship with the pumps power, the fiber′s length and the fiber′s dispersion characteristic as well. From abnormal dispersion region to normal dispersion region, the bandwidth reduced and became flattened. Assume the fiber′s second-order dispersion keeps constant, with the increase of the fiber′s fourth-order dispersion, the bandwidth is reduced accordingly. By using multi-section fiber arrangement, the parametric gain can be flattened by adjusting the fiber′s parameters.