用平面波展开法对光子晶体光纤中电磁场的Maxwell方程组进行了求解。将光纤截面作为超元胞衍生出一个无边界的二维周期性系统，光纤纤芯等效为光子晶体中的缺陷，借助平面波法对其性质进行研究，模拟了半导体中的超格子。运用上述超格子模型，对与纤芯同列孔半径可变的高双折射及与包层中纤芯距离最近的孔半径可变的色散平坦光子晶体光纤的光学性质进行了研究，发现与纤芯同列的孔半径变化时，其双折射比传统光纤更强，而当包层中距离纤芯最近的孔半径取特定值时，可得到近零色散平坦光纤并在大范围内获得反常色散。与传统光纤和普通光子晶体光纤相比，这种新型的色散平坦光纤在密集波分复用（DWDM）光通信系统中具有更高的应用价值。

he Maxwell equations for the propagation of electromagnetic waves in photonic crystal fibers are solved with plane wave method. The cross section of the photonic crystal fiber is taken as a big unit cell and an infinite twodimensional periodic system is generated, thus the core is regarded as a defect in photonic crystal. The properties of a new model of high birefringence photonic crystal fibers (PCB) and that of dispersion flattened PCB are studied respectively with the supercell model described above. It is found that birefringence in the model is higher than that in conventional fibers when the diameter of the holes in the same line with the core varies. Moreover, in the new model of dispersion flattened PCB, a zero dispersion flattened fiber can be obtained when the diameter of the holes closest to the core takes a specific value. The new dispersion flattened PCB will have great potential in optical communication systems.