运用具有三角形孔格子结构的光子晶体光纤(PCF)的近似经验关系与等效折射率模型相结合的方法来研究PCF的非线性。总结更为简捷的经验关系式进行计算,避开复杂的全矢量计算,得到了PCF基模和空间填充基模的有效折射率。利用等效折射率模型,以传统的阶跃光纤等效替代PCF,以光纤的数值孔径作为两个模型的关联点,得到了PCF的有效纤芯面积的简洁表达式。并在此基础上全面讨论了PCF的非线性与其结构参数及材料参数之间的关系,得到了与实际材料非线性相吻合的结论。 The PCF nonlinearity was studied by using the approximate empirical relationship of a photonic crystal fiber (PCF) with a triangular cell lattice structure and an equivalent refractive index model. Summarizing the more simple empirical relationship calculation, avoiding the complex full-vector calculation, the effective refractive index of the PCF and the space-filled base is obtained. By using the equivalent refractive index model, the traditional equivalent of step fiber is replaced by PCF, and the concavity expression of the effective core area of ​​PCF is obtained by using the numerical aperture of the fiber as the correlation point of the two models. On this basis, the relationship between nonlinearity of PCF and its structural parameters and material parameters is discussed comprehensively, and the conclusion is obtained that it is consistent with the actual material nonlinearity.