采用平面波展开法研究了含点缺陷正方结构二维函数光子晶体的带隙结构、缺陷模式和缺陷模式的本征场分布。选取介质柱的折射率为空间位置的分布函数，其参数可通过改变施加电场、光场的强度来调节。研究结果表明，通过调节介质柱参数，能够实现带隙结构、带隙位置、缺陷模式及缺陷模式的本征场分布的可调，该研究为相关光学器件的设计提供了理论依据和设计方法。

As for a two-dimensional function photonic crystal with square structure and point defects, its band gap structure, defect modes and eigenfield distribution of defect modes are studied by using the plane wave expansion method. The refractive index of the dielectric column is chosen as a spatial distribution function, whose coefficients can be adjusted by the altering of the applied electric field and the light field intensities. The research results show that, the adjustability of band gap structure, band gap position, defect modes and eigenfield distribution of defect modes can be realized by adjusting the parameters of the dielectric column, which provides an important theoretical basis and design method for the design of related optical devices.