对一种新型基于结构性改变的光子晶体光纤光栅原理进行了研究。采用多极法分析了结构性改变对折射率的影响,得到有效折射率与包层气孔塌缩之间的关系,建立了结构性改变光子晶体光纤光栅模型。利用耦合模理论对所成光栅性能进行了分析,重点研究了包层空气孔层数、空气孔占空比、气孔塌缩程度对光栅谐振波长、带宽的影响。研究结果表明,光子晶体光纤包层空气孔周期性塌缩可以形成光栅;空气孔塌缩程度和塌缩包络对有效折射率的大小和分布都有影响;空气孔层数增加,光栅谐振波长出现蓝移,带宽变宽,谐振强度减弱;相同光纤结构下,空气孔塌缩程度增加,光栅谐振波长出现红移,谐振带宽变窄。 A new type of photonic crystal fiber grating based on structural change has been studied. The influence of the structural change on the refractive index was analyzed by multipole method. The relationship between the effective refractive index and the collapse of the cladding pores was obtained. A model of structurally modified photonic crystal fiber grating was established. The performance of the grating was analyzed by the coupled-mode theory. The effects of the number of air-hole layers, the duty ratio of air holes and the degree of pore collapse on the grating resonant wavelength and bandwidth were studied emphatically. The results show that the periodic collapse of photonic crystal fiber cladding air holes can form a grating. The degree of air hole collapse and the collapse envelope have an impact on the size and distribution of effective refractive index. The number of air holes increases, the grating resonant wavelength Blue shift occurs, bandwidth broadens, and the resonance intensity is weakened. Under the same optical fiber structure, the degree of air hole collapse increases, the grating resonant wavelength shifts red and the resonance bandwidth narrows.