Huang Xue-Feng, Chen Zhe-Min, Shao Li-Yang, Cen Ke-Fa, Sheng De-Ren, Chen Jun, Zhou Hao
Institute for Thermal Power Engineering, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
Appl Opt. 2008 Feb 1;47(4):504-11. doi: 10.1364/ao.47.000504.
A refractive index sensor based on the thinned and microstructure fiber Bragg grating (ThMs-FBG) was proposed and realized as a chemical sensing. The numerical simulation for the reflectance spectrum of the ThMs-FBG was calculated and the phase shift down-peak could be observed from the reflectance spectrum. Many factors influencing the reflectance spectrum were considered in detail for simulation, including the etched depth, length, and position. The sandwich-solution etching method was utilized to realize the microstructure of the ThMs-FBG, and the photographs of the microstructure were obtained. Experimental results demonstrated that the reflectance spectrum, phase shift down-peak wavelength, and reflected optical intensity of the ThMs-FBG all depended on the surrounding refractive index. However, only the down-peak wavelength of the ThMs-FBG changed with the surrounding temperature. Under the condition that the length and cladding diameter of the ThMs-FBG microstructure were 800 and 14 mum, respectively, and the position of the microstructure of the ThMs-FBG is in the middle of grating region, the refractive index sensitivity of the ThMs-FBG was 0.79 nm/refractive index unit with the wide range of 1.33-1.457 and a high resolution of 1.2 x 10(-3). The temperature sensitivity was 0.0103 nm/ degrees C, which was approximately equal to that of common FBG.
提出并实现了一种基于薄化微结构光纤布拉格光栅（ThMs-FBG）的折射率传感器用于化学传感。计算了ThMs-FBG反射光谱的数值模拟，并且能从反射光谱中观察到相移下峰。在模拟中详细考虑了许多影响反射光谱的因素，包括蚀刻深度、长度和位置。采用三明治溶液蚀刻法实现了ThMs-FBG的微结构，并获得了微结构的照片。实验结果表明，ThMs-FBG的反射光谱、相移下峰波长和反射光强度均取决于周围折射率。然而，只有ThMs-FBG的下峰波长随周围温度变化。在ThMs-FBG微结构的长度和包层直径分别为800μm和14μm，且ThMs-FBG微结构位置位于光栅区域中间的条件下，ThMs-FBG在1.33 - 1.457的宽范围内折射率灵敏度为0.79nm/折射率单位，分辨率高达1.2×10⁻³。温度灵敏度为0.0103nm/℃，与普通FBG大致相当。
