中文摘要：

提出了一种新型的、基于单个径向渐变折射率（GRIN）透镜的1×N光纤耦合方法，并基于水平入射以及垂直斜面入射光线的传播方程建立了用于求解点光源发出的光束在GRIN透镜斜面入射后的成像点的计算方法。通过将透镜前端面加工成多斜面棱镜，将输入光分为多束，光束聚焦位置可以通过系统参数来调整；被分割开的光束经会聚、优化像差后，实现1×N低损耗耦合，并进行了仿真研究；通过优化斜面倾角、物距等关键参数实现了光纤低损耗耦合。该设计方案结构简单，易于装配，为各类光子晶体光纤、多芯光纤、光纤组束和光纤合光提供了实用的耦合方法。

英文摘要：

A novel method with a single gradient index （GRIN） lens for 1×N fiber coupling is proposed. A calculation and design method is founded to calculate beam focus position when a pointolite is illuminating an angular surface of a GRIN lens. In coupling module, the GRIN lens has one polyhedral end which is taken as the input port to split input light into several beams, and split beams get focused through GRIN lens. Beam focus position can be adjusted by some system parameters. These beams get focused through the GRIN lens, and couple into output fibers and fiber cores separately, meanwhile aberration is corrected. The simulation results show that the coupling models in different applying situations have high coupling efficiency by optimizing some key parameters, e.g. tilt angle of surfaces and object distance. It can be proved that the coupling method is simple in structure and easy to assemble. It provides a practical coupling method for variety of photonic crystal fibers, multi-core fibers, fiber bundle and fiber combining.