利用有限差分法和耦合模理论分析了光子晶体光纤结构参数等因素对光栅周期调节长周期光栅谐振波长作用的影响，结果表明：对于同种光纤，可通过增大或减小光栅周期来减小或增大谐振波长；若占空比f增大或减小，可通过减小或增大光栅周期来保持谐振波长不变；若比例系数M增大或减小，可以成正比增大或减小光栅周期来保持谐振波长不变；在只是空气孔层数增加的系列光纤中，在长波处，为取得同一谐振波长，光栅周期需要增大数个m，但在短波处则正好相反；内层气孔对光栅周期调节谐振波长的作用影响较大，而第5层以外各层的影响十分微弱。综合利用这些规律，可以快捷地选择合适的光栅周期，高效率地制备有合适谐振波长的光子晶体光纤长周期光栅。

With the finite difference method and the coupled mode theory, it was analyzed that photonic crystal fiber (PCF)-s structure parameters affected the adjusting action of long period grating (LPG)-s grating period on the resonant wavelength. The results showed that, for the same kind of PCF, it is feasible to decrease or increase resonant wavelength by increasing or decreasing grating period. If duty cycle f of PCF is increased or decreased, the resonant wavelength can be kept unchanged by decreasing or increasing grating period. If the scale coefficient M of PCF is increased or decreased, the resonant wavelength can be kept unchanged by increasing or decreasing grating period. For the PCF series only with the layer numbers of air hole increased, in the long-wavelength region, the grating period should be increased several ms to keep the resonant wavelength unchanged, while it was just the opposite in the short-wavelength region. The air holes in the inner layers greatly affect the adjusting action of grating period on the resonant wavelength, while the layers outside of the fifth layer affect the action very faintly. Using these regularities, it is portable to choose appropriate grating period, and high-effectively prepare LPG in PCF with appropriate resonant wavelength.