提出了一种在二维三角晶格光子晶体线缺陷波导中放置椭圆空气孔的耦合腔波导结构。基于平面波展开法, 利用MPB对线缺陷波导的能带结构进行了计算并给出能带图。基于时域有限差分法(FDTD), 利用MEEP对椭圆空气孔在波导中的排列方式、数量、尺寸进行优化设计, 并对频率位于微腔共振频率处的光波在耦合腔波导结构中的品质因子和传输特性进行研究与比较, 给出了电场分布图。仿真结果表明, 当椭圆空气孔的长轴方向纵向排列时, 相应的微腔共振频率在光子禁带内可获得90%以上的透射率, 对应的品质因子Q可达104量级; 选择合适的参数, 获得的Q可高达107量级, 对应共振频率的透射率仍在60%以上。

A novel coupled-cavity waveguide based on two-dimensional triangular lattice photonic crystals was proposed. This structure was composed of the line-defect waveguides, resonant micro-cavity, and ellipse-holes which are located between line-defect waveguide and resonant micro-cavity. The band structure of line-defect waveguide was simulated by the method of the plane-wave expansion. The transmission characteristics and quality factor of the coupled-cavity waveguides were investigated by the finite-difference time-domain (FDTD) method. By optimizing the structural parameters such as amount, size, and arrangement of ellipse-holes between the resonant micro-cavity and the line-defect waveguide, a 90% transmission efficiency was obtained with a Q-factor of 104. Then, appropriate parameters were selected, a high Q-factor of 107 was achieved, the transmission efficiency corresponding to the resonance frequency was still above 60%.