利用光纤产生涡旋光对提高轨道角动量通信系统的性能、降低轨道角动量通信系统的成本等方面有重要的应用价值。少模光纤是一种只存在基模和低阶模式的光纤, 结合光纤中的耦合模理论和涡旋光的产生原理, 仿真分析了入射角度对少模光纤中一阶模式激发效率的影响, 实验在少模光纤中产生了一阶模式TM01、TE01和HEeven21, 并将一阶矢量光束HEeven21与HEodd21模式叠加产生涡旋光。偏振检测和三角形衍射实验表明, 少模光纤产生的涡旋光是圆偏振光, 拓扑荷数l=1。利用少模光纤可为实验中涡旋光的产生提供一种简单、低成本的方法。

The generation of vortex light in the fiber has an important application value in improving the performance and reducing the cost of orbital angular momentum communication system. Few-mode fiber is a kind of optical fiber with fundamental mode and low order modes. According to the coupling mode theory and the generation principle of vortex light, the effect of the incident angle on the excitation efficiency of the first order mode in the few-mode fiber is simulated. The first order modes of TM01, TE01 and HEeven21 are generated in the few-mode fiber, and the first order vector beams with HEeven21 and HEodd21 modes are superimposed to produce vortex light. The results of polarization detection and triangular diffraction show that the vortex light produced by the few-mode fiber is circularly polarized light and the topological charge (l) is 1. The use of few-mode fiber in the experiment provides a simple and low-cost method for the producing of vortex light.