基于双洛伦兹型光纤光栅快慢光的超高灵敏度传感器研究

Ultra-high sensitivity fiber sensor with slow/fast light using fiber gratings has important applications in time-varying signal high-fidelity sensing, gravitational waves measuring and so on. The current proposed fiber sensors with grating slow light have the intrinsic deficiencies in terms of rigorous demands for gratings, narrow bandwidth and the failure to achieve time-varying signal high-fidelity pickup. Based on our research background in fiber grating slow light and interferometric sensor, we propose a new scheme of ultra-high sensitivity fiber sensor using double-Lorentzian fiber gratings in this project. We will insert double-Lorentzian fiber gratings into the interferometric fiber sensor. Ultra-high sensitivity sensing can be achieved by constructing a push-pull configuration which introduces slow and fast light in the two arms of the interferometer respectively. We will study the double-Lorentzian fiber grating slow light and enhancement of the sensitivity of fiber sensor both theoretically and experimentally. We will also study the signal fidelity-pickup using phase generated carrier method and the large bandwidth of double-Lorentzian fiber grating slow light. In addition, we will use active fiber grating slow light to further improve the sensitivity. The completion of this project will present us a new approach of slow light fiber sensor system improvement and perfection. A significant breakthrough is expected to be made in ultra-high sensitivity fidelity-pickup interferometric slow light fiber sensor.

基于光栅快慢光的超高灵敏度光纤传感器在微振动信号保真拾取、引力波探测等领域具有重要的应用前景和研究价值。针对当前光栅快慢光传感器对光栅要求苛刻、工作带宽较窄且不能实现时变信号的保真拾取等缺点，本项目拟在课题组前期工作的基础上，提出一种基于双洛伦兹型光栅快慢光的超高灵敏度干涉型光纤传感器方案。该方案将双洛伦兹型光纤光栅接入干涉型光纤传感器中，通过在传感器的两个臂分别引入快光和慢光的推挽式快慢光探头结构，并结合相位生成载波技术，实现超高灵敏度的微振动信号保真拾取。拟采用理论与实验相结合的方法，深入研究双洛伦兹型光纤光栅快慢光和传感器灵敏度增强以及快慢光微振动传感保真拾取等方面的理论和技术，并通过有源光纤光栅快慢光技术进一步提高其灵敏度。本项目的完成将为基于快慢光的干涉型光纤传感器实现微振动信号的保真拾取提供一种新的方案，并将为超高灵敏度快慢光传感系统的改进与完善提供新的思路。

基于快慢光的超高灵敏度光纤传感器在微振动信号保真拾取、引力波探测等领域具有重要的应用前景和研究价值。本项目在课题组前期研究基础上，围绕快慢光光纤传感器灵敏度增强展开理论与实验研究。将双洛伦兹型光纤光栅熔接在马赫曾德尔干涉仪的一个臂中，当改变激光器波长，双洛伦兹型光纤光栅工作在慢光状态下，系统的应变灵敏度提高到1.3倍；而当双洛伦兹型光纤光栅工作在快光状态下，系统的应变灵敏度降低到0.71倍。将有源光纤光栅熔接在迈克尔逊干涉仪中，当改变激光器波长使其工作在慢光峰时，可以获得1.83 弧度的相移，比非慢光区域增加了4倍。此外，采用有源光纤光栅还可以通过调节光栅的泵浦光功率来获得稳定的传感灵敏度并获得灵敏度可调的传感系统。将布里渊慢光引入马赫曾德尔干涉仪的一个臂中，用以检测外界振动引起的布里渊激光器频移。在实验中，系统灵敏度获得了1.57倍增强，并利用相位载波技术实现了振动信号的保真拾取。在项目经费支持下，发表SCI论文8篇，EI论文3篇，另有一篇SCI论文已收到录用通知；申报国家发明专利一项，培养硕士研究生三名。.总体来说，本项目达成项目各项预期目标，项目取得成果完成预期成果各项指标。本项目的完成为基于快慢光的干涉型光纤传感器实现微振动信号的保真拾取提供了新的方案，并为超高灵敏度快慢光传感系统的改进与完善提供了新的思路。