温度场对空间光到单模光纤耦合效率影响分析

Analyze the impact of the space temperature field on the spatial light to single mode fiber coupling

为提高空间光到单模光纤耦合效率的温度适应性,需要对聚焦透镜组和光纤的结构形式进行优化设计。基于热膨胀和光纤耦合理论,提出了一种前端法兰对称式结构,并针对两镜式聚焦透镜组,计算了温度场与焦点轴向位置、径向位置、光纤模场变化的关系,推导了耦合效率随温度变化公式。利用Abaqus有限元软件分析了前端法兰和底部两种结构形式温度场与焦点位置相对变化量,结果表明:相同温度变化,前端法兰对称式结构焦点径向相对变化量小、空间光到光纤耦合效率更高。该结构形式温度适应性高,为聚焦透镜组和光纤结构形式设计提供依据。

In order to improve the temperature adaptability of the coupling efficiency of spatial light to single-mode fiber,it is necessary to optimize the structure of the focusing lens group and the fiber.Based on thermal expansion and fiber coupling theory,a symmetrical structure of front flange is proposed.For the two-lens group,the relationship between the temperature field and the change of the axial,radial position of the focus and MFD of the optical fiber is calculated,then the formula of coupling efficiency with the temperature is derived.Abaqus finite element software is used to analyze,the results that with the same temperature change,the radial focus relative change of the symmetrical structure with front flange is small and the coupling efficiency is higher.This structure is high temperature adaptability,which provides basis for the design of focusing lens group and optical fiber structure.