利用耦合波导列提高光子晶体波导辐射

Enhancing the emission efficiency in photonic crystal waveguide with coupled waveguide arrays

将耦合波导列应用于光子晶体单模波导,提出一种提高光辐射的光子晶体结构.基于时域有限差分方法的理论研究表明,当将耦合波导列附加到单模光子晶体波导出口端的适当位置,使出射光分成若干强弱不一的光束,这些光束在传播空间通过干涉形成一定程度的汇聚,大大提高了光子晶体波导在水平方向的光辐射效率.另外,当耦合波导列的行数大于某固定值(2N=8)时,辐射质量基本保持不变,由此可获得最紧凑的器件结构.这种类型光子晶体在近场光学和集成光学等诸多方面有潜在的应用价值.

We propose a system of enhanced emission efficiency by employing coupled waveguide arrays to a single-mode photonic crystal waveguide. The FDTD simulation results show that, when the coupled waveguide arrays are placed properly at the exit plane of the single-mode photonic crystal waveguide, the output light can be split into many light beams, and the interference of these light beams can produce a focusing emission beam, which greatly enhances the emission efficiency. In addition, when the row number of the waveguide arrays is larger than a certain value （2N=8）, the state of the emission is nearly steady and the most compact structure can be obtained. This type of photonic crystal has potential applications in near-field optics or integrated optics.