摘要
提出了一种可同时测量温度、应变和折射率的光纤多参量复合传感器。该传感器由一个锥形相移布拉格光栅和全光纤马赫-曾德尔干涉仪级联构成,利用二者不同的传感特性实现三参数同时测量:锥形相移光栅用于实现应变和温度传感,马赫-曾德尔干涉仪用于实现折射率传感。进一步利用传递矩阵法分析了该传感器的三参数同时测量特性。通过实验测试可得该传感器的温度灵敏度、应变灵敏度和折射率灵敏度分别达到12.2 pm/℃、0.0213 dB/με和-344.81 dB/RIU。此外,该传感器还具有制造简单、反射式操作、灵敏度高等优点,在多参数测量中具有广泛的应用前景。
Objective Optical fiber sensors are a significant branch in the sensor field due to their compact structure,remote monitoring capabilities,and resistance to electromagnetic interference.As sensor technology advances and application demands increase, there is a growing need to monitor multiple parameters simultaneously. For instance, in marineecological monitoring and the petrochemical industry, simultaneous measurement of strain, temperature, and refractiveindex is essential. Using single or dual-parameter sensors requires deploying multiple different sensors, which complicatesthe sensing system. Existing optical fiber sensors typically measure only two parameters, and three-parameter sensors arerare and complex, posing challenges for simultaneous multi-parameter measurement in complex environments. Therefore,designing a compact and flexible three-parameter sensor for simultaneous measurement of strain, temperature, andrefractive index is both significant and promising. In this paper, we propose a hybrid structure fiber sensor that integrates atapered phase-shifted Bragg grating and a Mach ‒ Zehnder interferometer. By leveraging the complementary sensingcharacteristics of these two components, the sensor can simultaneously measure strain, temperature, and refractive index,offering a novel solution for multi-parameter measurement scenarios in environmental monitoring and the petrochemicalindustry.Methods The hybrid sensor utilizes the complementary sensing characteristics of the tapered phase-shifted Bragg gratingand the Mach ‒ Zehnder interferometer to simultaneously measure strain, temperature, and refractive index. The sensingprinciples for strain and temperature of the tapered phase-shifted Bragg grating and strain and refractive index of theMach ‒ Zehnder interferometer are analyzed, demonstrating their complementary nature. A Mach ‒ Zehnder interferometerbased on multimode fiber (MMF) and photonic crystal fiber (PCF) is constructed. The influence of PCF length on thespectrum is tested to determine the optimal length. The tapered phase-shift grating is fabricated using arc discharge from afusion welding machine, with precise control of the minimum radius to enhance strain sensitivity while maintainingstructural strength. Silver deposition is used on the fiber end face to enable reflective monitoring, reducing sensor lengthand easing device layout. Finally, a sensing test system for strain, temperature, and refractive index is established, and theperformance of the three parameters is evaluated. The matrix method is used to eliminate cross-sensitivity between theparameters, enabling simultaneous measurement.Results and Discussions The reflection spectrum of the sensor is monitored using a spectral analyzer and a broadbandlight source. After tapering the initial fiber Bragg grating (FBG), a transmission window is created in the middle of thereflection peak (Fig. 2). The spectral change in this window characterizes the response of the tapered phase-shifted gratingto strain and temperature, while the intensity change at 1560 nm indicates the Mach‒Zehnder interferometer’s response torefractive index and strain. Strain sensing experiments show that with strain increasing from 0 to 300 με, the centralwavelength shift of the conical PS-FBG transmission window is 0.59 nm, with a reflection peak intensity difference of6.42 dB, corresponding to strain responses of 1.88 pm/ με and 0.0213 dB/ με . The intensity change at 1560 nm is-0.664 dB, with a sensitivity of 0.0022 dB/με (Fig. 4). Temperature experiments show no change in the phase shift of thephase-shifted grating as the temperature rises from room temperature to 120 ℃, with a wavelength modulation temperaturesensitivity of 12.2 pm/℃ and an MZI temperature sensitivity of 0.0014 dB/℃ (Fig. 5). Refractive index experimentsdemonstrate no change in the conical PS-FBG spectrum as the refractive index increases from 1.3330 to 1.3707, with anMZI refractive index sensitivity of -344.81 dB/RIU (Fig. 6). The sensor exhibits good linearity in strain, temperature,and refractive index measurements across the experimental range.Conclusions A hybrid structure fiber three-parameter sensor based on a tapered phase-shifted Bragg grating and an MZIhas been proposed and experimentally validated. The tapered PS-FBG is created through arc discharge, and the MZI isconstructed using MMF and PCF. These components are cascaded and silver-plated on the end face. By leveraging theadvantages of the tapered PS-FBG for strain and temperature sensing and the MZI for refractive index sensing, the sensorachieves simultaneous measurement of strain, temperature, and refractive index. Experimental results indicate that thesensor’s temperature sensitivity is 12.2 pm/℃ , strain sensitivity is 0.0213 dB/με, and refractive index sensitivity is− 344.81 dB/RIU, all demonstrating good linearity. The proposed hybrid structure sensor offers a compact design, lowmanufacturing cost, and flexible use, making it a valuable tool for various applications.
作者
曾理
孙小燕
董欣然
胡友旺
段吉安
Zeng Li;Sun Xiaoyan;Dong Xinran;Hu Youwang;Duan Ji’an(School of Intelligent Engineering and Intelligent Manufacturing,Hunan University of Technology and Business,Changsha 410205,Hunan,China;Xiangjiang Laboratory,Changsha 410205,Hunan,China;College of Mechanical and Electrical Engineering,Central South University,Changsha 410083,Hunan,China;College of Mechanical and Intelligent Manufacturing,Central South University of Forestry and Technology,Changsha 410004,Hunan,China)
出处
《光学学报》
CSCD
北大核心
2024年第22期70-78,共9页
Acta Optica Sinica
基金
国家自然科学基金青年科学基金(52005521)
湘江实验室重大项目(22XJ01002)。
关键词
光纤传感器
多参数传感器
相移布拉格光栅
马赫-曾德尔干涉仪
optical fiber sensor
multi-parameter sensor
phase-shifted fiber Bragg grating
Mach‒Zehnder interferometer
