组合型光纤相位共轭器的数值模拟

Analysis of stimulated Brillouin scattering in combined optical fiber

组合光纤是一种结合了小口径光纤SBS阈值低和大口径光纤损伤阈值高的特点而形成的新型光纤相位共轭器。通过建立数学模型,数值计算了组合光纤中SBS形成的过程,并对其特性参数进行了一定的理论分析。结果表明组合光纤不但可以大幅度降低SBS阈值、获得高反射率和扩大动态范围,而且通过优化其几何尺寸可以抑制Stokes波形的波动现象并显著压缩泵浦光脉冲。

A theoretical model for the new type phaseconjugator using combined fiber, which is composed of two fibers with different core diameters connected by an internal taper, is established. By numerical calculation the whole SBS process in combined fiber has been illustrated clearly and its key characters have been discussed. The results show that the combined fiber can greatly decrease SBS threshold and improve reflectivity while behaves a much larger dynamic range. Furthermore, with optimum dimensions, the combined fiber can suppress the power modulation of Stokes wave and show a potentiality to considerably compress laser pulse.