基于近PMTP区域双峰谐振效应的长周期光纤光栅应变传感理论分析

发布时间：2018-11-21 09:17

【摘要】：利用长周期光纤光栅(LPFG)的双峰谐振效应,结合LPFG传感器工作于近相位匹配转折点(PMTP)附近的高灵敏度,提出了一种新型的长周期光纤光栅应变传感器的设计方法。利用LPFG相位匹配条件,分析了长周期光纤光栅近PMTP附近的双峰谐振特性、应变传感特性,发现双峰波长间距对微小应变具有很高的响应度和线性度。进一步讨论了光栅结构参数和包层直径对双峰LPFG应变灵敏度的影响,发现光栅周期对该传感器的应变灵敏度、线性度和应变测量范围具有很大的影响;光栅长度对谐振峰高度和宽度有较大影响,直接关系到传感器寻峰精度;通过增大包层直径,可以进一步增大应变灵敏度。结果表明,通过选取适合的光栅结构参量和包层半径,该传感器应变灵敏度可比一般长周期光纤光栅应变传感器的应变灵敏度提高2个数量级。这为设计高应变灵敏度双峰谐振LPFG应变传感器提供了结构优化的理论支持。
[Abstract]:Based on the bimodal resonance effect of long-period fiber Bragg grating (LPFG) and the high sensitivity of the LPFG sensor working near the phase matching turning point (PMTP), a new design method of the long-period fiber Bragg grating strain sensor is proposed. Based on the LPFG phase matching condition, the bimodal resonance and strain sensing characteristics of the long period fiber grating near PMTP are analyzed. It is found that the wavelength spacing between the two peaks has a high responsivity and linearity to the micro strain. The effects of grating structure parameters and cladding diameter on strain sensitivity of bimodal LPFG are discussed. It is found that grating period has great influence on strain sensitivity, linearity and strain measurement range of the sensor. The grating length has a great influence on the height and width of the resonant peak, which is directly related to the peak finding accuracy of the sensor, and the strain sensitivity can be further increased by increasing the cladding diameter. The results show that the strain sensitivity of the sensor is two orders of magnitude higher than that of the conventional long-period fiber Bragg grating strain sensor by selecting suitable grating structure parameters and cladding radius. This provides theoretical support for the design of high strain sensitivity bimodal resonant LPFG strain sensor.
【作者单位】：上海理工大学理学院光电功能薄膜实验室;
【基金】：国家自然科学基金(60777035) 教育部科学技术研究重点项目(208040) 上海市教育委员会科研创新重点项目(11ZZ131) 上海市重点学科建设项目(S30502) 沪江基金(B14004)
【分类号】：TP212

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