磁流体填充的光子晶体光纤Bragg光栅三参量同时传感特性研究

Three-parameter measurement based on cascaded Bragg gratings in magnetic fluid-infiltrated photonic crystal fiber

基于光子晶体光纤(PCF)包层空气孔灵活的结构设计,将磁流体填充的PCF(MF-PCF)和普通PCF进行焊接,并在其纤芯区域刻蚀Bragg光栅,提出一种能够同时测量温度、磁场和应变的PCFBG传感器。基于模式耦合理论以及传输矩阵法,结合PCF中基模以及高阶光波模式的不同传感特性,通过分析热光效应、磁光效应以及弹光效应对模型不同光波模式的影响,探究谐振波峰反射谱响应特性。实验结果表明,本文的PCFBG传感器,温度灵敏度最高可达13.97pm/℃,磁场灵敏度最高达10.04pm/mT,应变灵敏度最高达1.223pm/με;且谐振反射光谱的漂移量与温度、磁场以及应变的变化具有良好的线性关系。通过设计相应的三参量矩阵解调算法,可实现温度、应变以及磁场的同时测量,从而有效降低传感成本,拓宽传感思路,具有一定的应用价值。

Based on the flexible structure design of photonic crystal fiber cladding air holes,the magnetic fluid-infiltrated ph otonic crystal fiber （MF-PCF） and common-PCF were w elded together.By etching Bragg grating in the fiber core area, a kind of PCF-Bragg grating sensors which can simultaneously measure temperatu re,magnetic field and strain is put forward.Based on mode coupling theory and transfer matrix method ,combining different sensing properties of core mode and higher-order mode in PCF,the resonance wavelength-shift characteristics are carried out by analyzing the influence of thermal effect, magneto-optic effect and elastic-optic effect on Bragg grating.The experimenta l resul ts show that,the sensor has high sensitivity response to temperature,magnetic field and strain,an d the resonant wavelength-shift has a good linear relationship with temperature,magnetic fiel d and strain.The highest temperature sensitivity can reach 13.97pm/℃,the magnetic field sensitivity is 10.04pm/mT,and the strain sensitivity is 1.223pm/με.Through d esigning appropriate three-parameter matrix demodulation algorithm,we can reali ze the measurement of temperature,strain and magnetic field simultaneously,and this method can effecti vely reduce the cost of sensor and broaden the sensing approach.