基于高阶空间模式动态串扰抑制的少模光纤链路高灵敏度故障检测研究

本项目提出一种基于高阶空间模式动态串扰抑制的少模光纤（FMF）链路高灵敏度故障检测方法，解决基模LP01故障检测灵敏度受限这一关键科学问题。本项目以研究高阶空间模式瑞利散射特性及表征为基础，探索适用于FMF链路的高阶空间模式故障检测方法，剖析FMF熔接故障点处高阶空间模式损耗机理，研究高效率、低损耗的高阶空间模式激发与分离技术，确定动态空间模式串扰累积效应条件下的故障检灵敏度极致优化方法，提出并验证基于高阶空间模式动态串扰抑制的高灵敏度故障检测实现方案，最终完成6模光纤故障检测的原理性实验，故障检测灵敏度优于0.1dB。该方法通过利用高阶空间模式的高灵敏度检测特性，极大改善了FMF链路故障检测灵敏度及定位精度，且可高效抑制动态空间模式串扰对故障检测灵敏度的影响，能够满足FMF链路故障检测的实际需求。课题的研究对于确保FMF链路可靠、高效运行，推进长距离大容量光纤网络的发展进程有重要意义。

In this project, a fault detection method for few-mode fiber (FMF) link based on high-order spatial mode with dynamic crosstalk suppression is proposed, which solves the key scientific problem of limited fault detection sensitivity of basic-mode LP01. The main efforts in this project will be focused on exploring the high-order spatial mode fault detection method for FMF link based on properties and characterization of Rayleigh scattering in higher-order spatial modes, analyzing the mechanism of high-order spatial mode loss at FMF fault point, researching the high-order spatial mode excitation and separation technology with high efficiency and low loss, and implementing the sensitivity optimal optimization method of high-order spatial mode fault detection when there is dynamic spatial mode crosstalk accumulation effect in the FMF link. On the basis of the above work, an implementation scheme of high-sensitivity fault detection based on high-order mode with dynamic crosstalk suppression is proposed and will be verified experimentally, and the ultimate goal of the scheme is to realize a principal experiment of six mode fiber fault detection in which the fault detection sensitivity is better than 0.1dB. This method can greatly improve the fault detection sensitivity and positioning accuracy by making use of the high-sensitivity detection characteristics of the high-order spatial mode, and it can effectively inhibit the influence of dynamic spatial mode crosstalk on fault detection sensitivity, which can meet the actual needs of FMF link fault detection. This research is of great significance to ensure the reliable and efficient operation of FMF link of FMF link and promote the development process of long-distance and high-capacity optical network.