频移干涉连续波空间域光纤腔衰荡传感方法及其应用的基础研究

Cavity ring-down spectroscopy（CRDS） technique is one of the vital technology in the field of high sensitivity sensing. Fiber cavity ring-down sensing method can be applied to measure key parameters in the physical, chemical and biomedical field, which is an important trend of development of CRDS technique and is becoming the research focus nowadays. Due to the big loss of the cavity, the sensitivity of fiber cavity ring-down technology was difficultly impoved in the past several years, especially the sensitivity of gas measurement is far less than that by the traditional CRDS technique. Thus, there is an urgent need to develop new methods. Optical interference is one of the highest sensitive technology, and there are many unique advantages for the technique of fiber frequency-shifted interferometry(FSI). So the project proposes to combine fiber FSI and cavity ring-down(CRD), and to transform the signal processing of the CRD from time domain to spatial domain, which can reduce the performance requirements of the sensing system to light source and data acquisition, and can improve the stability of the system. The proposal needs to carry out the theory and characteristics of continuous-wave spatial-domain fiber cavity ring-down sensing, and to research the low-loss key components used by the fiber cavity ring-down sensing (such as various sensors and its multiplexing), to verify the novel method through many experiments of sensing multi-parameter. Besides, we will focuse on breakthroughs of key technology in the application of CO trace gas detection. There are very important scientific significance and practical values to explore a novel technology of optical fiber sensing with high sensitivity to monitor a variety of interdisciplinary parameters.

腔衰荡光谱技术一直是高灵敏度传感领域的关键技术之一，光纤腔衰荡传感方法能测量物理、化学和生物等多领域的关键参量，是腔衰荡光谱技术的重要发展趋势和当前研究热点。而光纤腔衰荡技术因空腔损耗大等原因，其灵敏度一直难以提高，尤其是气体测量的灵敏度远远不及传统腔衰荡光谱技术，迫切需要研发新的方法。光的干涉是灵敏度最高的技术之一，光纤频移干涉技术还具有许多独特优点，本项目据此提出将光纤频移干涉和腔衰荡两项高灵敏技术融合，使对腔衰荡信号的处理从时间域变到空间域，降低了系统对光源和信号采集等的过高要求，提高了系统稳定性。需要开展基于频移干涉的连续波空间域光纤腔衰荡传感理论和特性、光纤腔衰荡传感用低损耗关键器件（如传感器及其复用）的研究，并通过多参量传感实验进行验证，着重突破CO痕量气体检测应用的关键技术，对于探索实现一种具备监测多种跨学科参量的高灵敏光纤传感新技术，具有十分重要的科学意义和实用价值。

本项目组紧紧围绕项目任务书的研究内容与目标，开展了频移干涉连续波空间域光纤腔衰荡传感的理论和特性研究，重点研究了基于频移干涉光纤腔衰荡技术的气体检测方法，拓展了频移干涉技术在磁场测量、振动传感、超声检测、弱光栅反射率测量等方面的应用；此外，为了实现大规模光纤传感器的复用，开展了频移干涉技术在光纤法珀传感器、大规模弱光纤光栅复用方面的研究，同时研究了基于单臂频移干涉技术的光纤光栅复用以进一步提高空间分辨率。通过频移干涉和腔衰荡传感两项技术的结合，建立了复杂情况下频移干涉连续波空间域光纤腔衰荡传感理论模型，获得了频移干涉连续波空间域光纤腔衰荡传感新方法，并搭建完成相应的实验研究平台，掌握了其传感特性，揭示了其对气体、磁场、超声波、应力、温度、反射率等物理量、化学量和生物量传感的机理和特性，为本项目的新型传感方式提供理论依据。探索设计出 2种具有原创性、灵敏度更高的乙炔和甲烷气体传感器，在以乙炔为代表的痕量气体高灵敏度光纤腔衰荡传感的研究开发方面取得突破，灵敏度达到ppm量级；研究获得的频移干涉光纤腔衰荡磁场传感器具有灵敏度更高、无需光脉冲和快速探测、成本更低等优点，测量范围为8-850 Gs，测量灵敏度达到了0.00105 dB/Gs；研究获得的频移干涉光纤腔衰荡振动传感器实现了对0-3 kHz振动信号的传感，获得的加速度灵敏度为22.7 mV/g，对应的探测极限为1 m/s2。在国内外核心刊物与国际会议上发表相关学术论文14篇，其中EI检索14篇，SCI论文8篇，影响因子 2.0以上期刊发表 6篇，申请发明专利3项；已培养博硕士研究生 8名。