极限性能光频域反射仪关键技术研究

Optical reflectometry with long measurement range and high spatial resolution is an essential supporting technology for distributed optical fiber sensing system. The aim of this project is to study the key techniques of extremely high-performance optical frequency domain reflectometry. This research proposal is based upon the optical frequency domain reflectometry that has been developed by the proposer when he worked for Nippon Telegraph and Telephone Coporation (NTT) Laboratories, and has realized world-leading performance on the ratio of "measurement range" to "spatial resolution". By introducing ultra-fast frequency sweeping to enhance the ratio of frequency to distance, the influence of frequency noise caused by phase noise of light source and environmental perturbation on the spatial resolution will be suppressed, making high performance with long measurement range and high spatial resolution to be achieved. Main research topics including these shown below. (1)Theoretical analysis and optimum design of realizing the ultrafast frequency sweeping using nonlinear optical signal processing; (2) Mechanism of reducing the frequency of high-frequency electrical signals realized using optical methods; (3) Study on phase noise compensation of optical source; (4) Application exploration of high-performance optical frequency domain reflectometry. On the background of high demanding for optical sensing technologies by many industrial fields,the study of this project will provide very important scientific significance and very promising industrial prospects.

为了满足对于具有长距离、高空间分辨率的分布式光纤传感系统的需求，本项目研究实现极限性能光频域反射仪（OFDR）的关键技术。本研究立足于申请人在日本电信电话公司(NTT)所进行的具有世界领先“距离分辨率比”性能的OFDR技术前期研究工作基础上，通过导入极限高速扫频方法对光源进行线性频率扫描以提高频率距离比，降低由于光源相位噪声以及外部环境干扰所造成的频率噪声对空间分辨率的影响，以达到长距离高空间分辨率的性能。主要研究内容包括：（1）利用非线性光信号处理过程实现极限高速扫频的原理分析和优化设计；（2）利用光学方法实现高频电信号降频的机制研究；（3）光源相位噪声补偿方法研究；（4）高性能光频域反射仪的应用研究。在国内各行各业对分布式光纤传感技术的需求逐年递增的背景下，本项目的研究具有重要的科学意义和产业应用前景。

项目研究计划执行过程中立足于前期研究工作基础上，通过导入极限高速扫频方法对光源进行线性频率扫描以提高频率距离比，降低由于光源相位噪声以及外部环境干扰所造成的频率噪声对空间分辨率的影响，以达到长距离高空间分辨率的性能。研究工作首先围绕高性能光反射仪所需扫频光源的产生，采用新型非线性光学光信号处理技术、激光注入锁定技术等提高激光扫频的速度及带宽，实现了达到100GHz宽度的激光扫频扩频，用于常规OFDR系统中，最终在2km测量距离上实现1.1mm的超高空间分辨率；同时，采用光学方法使高频电信号降频从而实现光反射仪的长距离测量，实现了30km测量范围内10cm的空间分辨率；在应用层面我们做了开放性的研究拓展，将光反射仪技术应用到远程检测光纤破坏传播现象“光纤熔合”、分布式振动传感等领域。项目共一年执行期，研究过程中总计发表论文21篇，其中SCI论文6篇，申请专利10项，培养在读博士研究生（包括硕博连读）7人。