光子晶体是以介电常数呈周期性排布且在光波长量级构建的人工微结构,利用其具有光子禁带这一特性可实现对光子的控制。引入线缺陷可形成光子晶体波导。以1.55μm的TE偏振光作为光源,用时域有限差分法计算并分析了二维正方晶格光子晶体三光波导方向耦合器在不同波导间距下的耦合长度及耦合效率分别与介质柱折射率和介质柱半径的变化关系。研究结果为1.55μm耦合器的结构设计及制备提供一定的理论指导。 Photonic crystals are artificial microstructures that are periodically arranged at dielectric constant and constructed on the order of the wavelength of light, and photon control can be achieved by virtue of its photon band gap. Inlet defects can form photonic crystal waveguides. Taking 1.55μm TE polarized light as the light source, the coupling length and coupling efficiency of three-waveguide directional coupler of two-dimensional square lattice photonic crystal were calculated and analyzed by finite difference time-domain method. Column radius changes. The research results provide some theoretical guidance for the structural design and preparation of 1.55μm coupler.