以二维三角晶格光子晶体为研究对象，在该光子晶体中引入两行平行的单模线缺陷波导，以一行耦合介质柱为间距，通过调节部分耦合介质柱的折射率，构筑了光子晶体异质结耦合波导光开关结构。利用平面波展开法和定向耦合原理计算了在不同入射光频率下，缺陷波导间耦合介质柱的折射率不同时的耦合长度，确定了合适的光子晶体异质结耦合波导光开关的结构参数。利用时域有限差分法研究了该光开关中耦合介质柱的折射率变化及异质结构介质柱的位置分布对光信号输出路径的影响。结果表明，通过改变该结构中耦合介质柱的折射率可以改变光的输出路径，可实现光的开关行为。并且异质结构介质柱位置的随机分布对该光开关的影响不大，有助于光子晶体新型滤波器、定向耦合器、波分复用器以及光开关等光子器件的研究。

A photonic crystal coupling structure is designed by introducing two parallel single-mode defect waveguides with the spacing of one row coupling rods in the two-dimensional (2D) triangular lattice array. By modulating the refractive index of some coupling rods, an optical switch based on coupled heterostructure photonic-crystal waveguides is constructed. The coupling lengths for different refractive indices of coupling rods at different frequencies are calculated to determine optimal structural parameters for the switch by the plane-wave expansion method and the principle of directional coupling. The effect of variations in the refractive index of the coupling rods and the position effect of the heterostructure coupled waveguides on the signal output channel are analyzed by using finite different time domain method. The simulation results show that it is an effective way to realize the switch function by appropriately tuning the refractive index of some coupling rods. The influence of the random distribution of the heterostructure on the switch is modest, which may contribute to the research over new kinds of optical filters, directional couplers, wavelength division multiplexers, optical switches and other photonic devices.