湖北师范大学 物理与电子科学学院, 湖北 黄石 435002
该文设计并制作了一款简易的拉锥空心光纤的高灵敏度传感器, 通过实验测量了其温度与应力特性。首先利用光纤熔接机在两段标准单模光纤之间熔接一段空心光纤, 再对准空心光纤中间位置进行放电, 同时运用两个步进电机在单模光纤两端施加一定的拉力, 这导致法布里-珀罗干涉仪转换为马赫-曾德尔干涉仪。实验结果表明, 此拉锥过程使光纤传感器的温度灵敏度从理论值0.85 pm/℃提升到69.1 pm/℃, 约提升了81.3倍, 轴向应变灵敏度最高可达3.6 pm/με。该器件具有体积小、结构简单和灵敏度高等特点, 在航空航天、医疗监测等领域具有广阔的应用前景。
温度传感器 应力传感器 空心光纤 拉锥 干涉仪 光纤熔接 temperature sensor strain sensor hollow fiber tapered interferometer optical fiber splicing
1 中国特种设备检测研究院, 北京 100029
2 国家市场监管结构健康监测技术创新中心, 北京 100029
针对用于起重机械结构健康监测的光纤布喇格光栅(FBG)应变传感器疲劳性能未知问题, 采用动态载荷与静态拉伸相结合的试验方法, 对起重机械钢结构疲劳损伤监测中的3种封装形式FBG应变传感器开展了疲劳性能研究, 分析了反映传感器性能的灵敏度系数、带宽、边摸抑制比、峰谷比、零点波长、动态应变分别随疲劳次数增加时的变化情况。试验结果表明: 3种封装方式的FBG应变传感器疲劳前后, 在加载、卸载相同载荷时, 灵敏度系数相差最大不超过0.1 pm/με, 带宽均值为0.19~0.23 nm, 峰谷比和边摸抑制比随疲劳次数的增加变化趋势相同, 零点波长变化最大值为0.31 nm, 动态应变符合二次指数函数分布特征。
光纤布喇格光栅应变传感器 金属结构 疲劳 可靠性 监测 fiber Bragg grating strain sensor metal structure fatigue reliability monitoring
Author Affiliations
Abstract
1 Key Laboratory of All Optical Network and Advanced Telecommunication Network of EMC, Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044, China
2 System Integration Department, China North Industries Corp., Beijing 100053, China
An in-fiber Mach-Zehnder interferometer is proposed for the discrimination of strain and temperature. The sensor is based on two cascaded standard single mode fibers using three peanut tapers fabricated by simple splicing. The cascaded structure excites more frequency components, which induce four sets of interference dips in the transmission spectrum. One set of the spectrum dips have different sensitivities to temperature and strain from those of the other three. The sensor can discriminate strain and temperature by monitoring the wavelength shifts of two spectrum dips. Repeated experiments are taken both for strain and temperature increasing and decreasing scenarios. Experimental results show that Dip 1 has an average strain sensitivity of -0.911 pm/με and an average temperature sensitivity of 49.98 pm/℃. The strain sensitivity for Dip 2 is negligible and its average temperature sensitivity is 60.52 pm/℃ The strain and temperature resolutions are ±3.82 με and ±0.33 ℃.
Mach-Zehnder interferometer peanut taper simultaneous measurement single mode fiber strain sensor temperature sensor Photonic Sensors
2023, 13(1): 230122
Author Affiliations
Abstract
Flexible strain sensors play an important role in electronic skins, wearable medical devices, and advanced robots. Herein, a highly sensitive and fast response optical strain sensor with two evanescently coupled optical micro/nanofibers (MNFs) embedded in a polydimethylsiloxane (PDMS) film is proposed. The strain sensor exhibits a gauge factor as high as 64.5 for strain ≤ 0.5% and a strain resolution of 0.0012% which corresponds to elongation of 120 nm on a 1 cm long device. As a proof-of-concept, highly sensitive fingertip pulse measurement is realized. The properties of fast temporal frequency response up to 30 kHz and a pressure sensitivity of 102 kPa?1 enable the sensor for sound detection. Such versatile sensor could be of great use in physiological signal monitoring, voice recognition and micro-displacement detection.Flexible strain sensors play an important role in electronic skins, wearable medical devices, and advanced robots. Herein, a highly sensitive and fast response optical strain sensor with two evanescently coupled optical micro/nanofibers (MNFs) embedded in a polydimethylsiloxane (PDMS) film is proposed. The strain sensor exhibits a gauge factor as high as 64.5 for strain ≤ 0.5% and a strain resolution of 0.0012% which corresponds to elongation of 120 nm on a 1 cm long device. As a proof-of-concept, highly sensitive fingertip pulse measurement is realized. The properties of fast temporal frequency response up to 30 kHz and a pressure sensitivity of 102 kPa?1 enable the sensor for sound detection. Such versatile sensor could be of great use in physiological signal monitoring, voice recognition and micro-displacement detection.
optical micro/nanofiber strain sensor pressure sensor micro-displacement directional coupler Opto-Electronic Advances
2022, 5(9): 210101
1 电子科技大学 电子科学与工程学院,四川 成都 611731
2 中国核动力研究设计院,四川 成都 610213
声表面波(SAW)延迟线作为传感器可对传感器进行编码,从而实现多点分布式测量,因而受到广泛研究。该文采用128°Y-X切向LiNbO3作为压电基底,制备了不同对数的叉指换能器(IDT) 的SAW延迟线,并研究了其应变特性。研究结果表明,IDT对数为10对、20对、30对时,SAW延迟线应变灵敏度分别为1, 727 5 ps/με、2, 046 7 ps/με、3, 256 6 ps/με。SAW延迟线的应变特性和应变方向与声波传播方向间的夹角有关,夹角为0°时,延迟时间随应变的增大而增大; 夹角为90°时,延迟时间随应变的增大而减小。利用夹角分别为0°和90°的SAW延迟线构成了差分结构的应变传感器。测试结果表明,该差分结构可抵消温度的影响,即温度变化时也可获得准确的应变。该文研究的差分结构延迟线有望在温度波动环境中测试应变时得到应用。
声表面波(SAW) 延迟线 应变传感器 差分结构 surface acoustic wave(SAW) delay line strain sensor LiNbO3 LiNbO3 differential structure
1 西北工业大学陕西省光信息技术重点实验室,陕西 西安 710072
2 西北大学物理学院,陕西 西安 710069
环境折射率和环境温度变化是影响光纤应变测量误差的主要因素。本文利用双模光纤纤芯双模式(LP01和LP11)支持特性设计了一款环境折射率不敏感的双模光纤(DMF)长周期光纤光栅LPFG)应变传感器。设计了传感器模型结构,制作了最优化参数的传感器样品。实验测试了DMF-LPFG传感结构对外部环境中应变、温度和折射率的响应。通过在单模光纤上用紫外激光刻写的布拉格光栅(FBG)解决了环境温度的交叉影响。轴向应变实验结果表明,该新型结构传感器在0 με~840 με应变范围内其轴向应变灵敏度可以达到-5.4 pm/με,该灵敏度值相比较于普通LPFG有很大提高。温度在25 ℃~80 ℃范围内其灵敏度为58.86 pm/℃,表现出较好的线性度。同时,传感器对环境折射率变化表现出不敏感特性。通过采用双参数矩阵对少模LPFG和FBG的应变和温度灵敏度进行处理,可以实现双参数的同时解调。该新型复合光栅结构具有良好的传感性能和工程应用前景。
双模光纤 长周期光纤光栅 布拉格光栅 应变传感器 温度补偿 dual mode fiber LPFG FBG strain sensor temperature compensation