基于群模式双折射设计的高灵敏度光子晶体光纤压力传感器研究

Fiber optic pressure sensors play an important role in exploitation and exploration of oil and gas, health monitoring of civil engineering, medical diagnoses in clinic, and national defense because of their unique advantages such as compact size, corrosion resistance, ease for multiplexing, and immunity to electromagnetic interference. Efforts to improve the performance of such kind of sensor are of great meaning. Photonic crystal fiber (PCF) provides a new platform which allows novel designs for fiber-optic devices and sensors, due to the large flexibility in designing of the air hole structure in its cross section. In order to overcome the issue that the existing fiber-optic pressure sensors suffer from low sensitivity, we propose the study of enhancing the sensitivity of a PCF pressure sensor based on tailoring its group modal birefringence. By effectively controlling and designing the property of group modal birefringence of the PCF, we successfully find a new machanism to enhance the pressure sensitivity. In this project, we plan to carry out following theoretical and experimental studies: (1) design and optimize the structure of a specialty PCF which is particular for polarimetric pressure sensing; (2) fabricate the designed PCF using the "stack and draw" technique; (3) construct a Sagnac interferometer using the fabricated PCF and experimentally investigate its pressure sensing characteristics, finally implement a pressure sensor with its sensitivity enhanced by 20 to 30 times compared with existing counterparts in literature.

光纤压力传感器在油气开采、国防安全、土木工程安全监测、临床医学诊断等领域发挥着重要的作用，如何提升其传感性能具有重要的研究意义和应用价值。光子晶体光纤因其截面结构设计上的巨大灵活性，为光纤传感器性能的提升提供了新的方式方法。针对传统光纤压力灵敏度低的问题，本项目开展基于群模式双折射设计的高灵敏度光子晶体光纤压力传感器研究，通过有效地控制光纤的模式双折射及其力学响应，为压力灵敏度增强找到新方向、新机制。本项目拟开展以下理论与实验方面的研究工作：(1) 基于有限元方法，计算PM-PCF的群模式双折射G和力学响应dB/dP；(2) 研究G和dB/dP随着各项结构参数的变化规律，对光纤结构进行优化设计，以提高波长漂移压力灵敏度；(3) 利用堆积法按照优化设计拉制出PM-PCF并制作Sagnac干涉仪，最终实现一种比现有同类型压力传感器灵敏度提升20至30倍的新型光纤压力传感器。

光纤压力传感器在油气开采、国防安全、土木工程安全监测、临床医学诊断等领域发挥着重要的作用，如何提升其传感性能具有重要的研究意义和应用价值。光子晶体光纤因其截面结构设计上的巨大灵活性，为光纤传感器性能的提升提供了新的方式方法。针对传统光纤压力灵敏度低的问题，本项目开展基于群模式双折射设计的高灵敏度光子晶体光纤压力传感器研究，通过有效地控制光纤的模式双折射及其力学响应，为压力灵敏度增强找到了新方向、新机制。本项目开展了以下理论与实验方面的研究工作：(1) 提出并设计了“蝴蝶形”和“哑铃形”空气孔分布的两种PM-PCF，基于有限元方法，计算了它们的群模式双折射G和相模式双折射B的压力响应系数dB/dP；(2) 研究了G和dB/dP随着空气孔尺寸、占空比等结构参数的变化规律，实现了对光纤结构的优化设计，所设计光纤压力灵敏度比现有PM-PCF提高了30倍；(3) 利用堆积法拉制出一种六空气孔PM-PCF，并利用它制作Sagnac干涉仪，获得了30dB对比度的干涉光谱和2.8nm/MPa的压力灵敏度；（4）提出了一种双芯PM-PCF，基于其双折射特性和超模式耦合特性，可实现压力和温度的同时测量。已取得的相关研究成果对未来光纤压力传感器增敏和温度补偿具有重要的应用价值。目前，相关成果共发表SCI期刊论文4篇、EI国际会议论文6篇，申请中国发明专利3项。