光纤光栅无应力毛细铜管封装及温度特性实验

为克服裸光纤布拉格光栅(FBG)脆弱易折断的缺点,提出了一种聚合物和毛细铜管相结合的封装工艺。先用丙烯酸酯对栅区进行二次涂覆,再将二次涂覆后的FBG封装在毛细铜管内,FBG在毛细铜管内处于有余长无应力状态,二次涂覆为裸FBG提供了有效的保护。测试结果表明,二次涂覆并没有改变FBG的温度灵敏度;较薄的涂覆厚度保证了涂覆的均匀性和涂覆后光谱的质量;无胶空管封装方式消除了聚合物内部应力对温度测量精度的影响。封装后的温度特性实验表明,FBG传感器线性度为0.999 29,温度灵敏度为13.675pm/℃,重复性较好。

Experimental study on temperature sensing characteristics of fiber Bragg grating packaged by copper capillary without strain

Due to the fragility of bare fiber Bragg grating(FBG),an approach of polymer and copper capillary packaging for FBG is proposed in this paper.The FBG is coated with acrylate.After the second coating,the FBG is packaged into a blank copper capillary.The FBG can expand or contract freely without strain.The second coating protects bare FBG from damage.The comparison of the experimental results between coated FBG and bare FBG indicates that the temperature sensitivity of coated FBG is nearly the same as that of bare FBG.The thin coating thickness guarantees that the coating thickness is uniform and the spectrum of coated FBG has a good shape.The influence on measurement precision of temperature from strain is decreased.The empirical results show that the coefficient between wavelength and temperature is 0.999 29,and the measurement sensitivity is 13.675 pm/℃.The temperature sensor has a good repeatability.