为了实现对环境温度的精确测量,提出了一种基于七芯光纤(seven-core fiber,SCF) 的迈克尔逊干涉型温度传感器。该传感器由单模光纤(single mode fiber,SMF)和SCF熔锥构成,当光由SMF进入SCF时,由于光纤直径的急剧变小,在光纤细锥区域会激发出SCF中的高阶模,这些高阶模与纤芯基模经SCF端面反射后,再次回到细锥区域时发生干涉,并经由SMF输出。制作了不同长度SCF的传感器样品,并分别进行了温度传感实验研究。温度响应实验结果表明,在20—160 ℃温度范围内,长度为47 mm的传感器的温度灵敏度为0.127 4 nm/℃,拟合线性系数为0.998 3,温度测量分辨率为0.007 8 ℃,稳定性实验测得传感器的测量标准偏差为0.289 6 ℃。该温度传感器结构紧凑、易于制作、成本低廉、灵敏度高且测量范围大,在温度监测领域具有一定的应用潜力。

In order to achieve accurate measurement of ambient temperature,a temperature sensor based on Michelson interferometer with seven-core fiber (SCF) is proposed. The sensor is fabricated by fusion spliced a taper in between a section of SCF and a single mode fiber (SMF).When light enters the SCF from the SMF,high-order modes of SCF in thin cone area will be excited for suddenly fiber diameter decreasing.After propagation in SCF,the high-order modes and the fundamental mode of fiber core are reflected by the end face of the SCF and continue transmitting in the SCF until reach the taper,these modes meet and interfere with each other,and then the accumulate interference is coupled to the SMF.The sensor samples with different SCF lengths are fabricated and experimentally investigated.The experimental results show that the temperature sensitivity of the sensor with length of 47 mm is 0.127 4 nm/℃ within the temperature range of 20—160 ℃,the fitting linear coefficient is 0.998 3,and the temperature resolution is 0.007 8 ℃.The measurement standard deviation of the sensor is 0.289 6 ℃ in the stability experiment.The temperature sensor has the advantages of easy fabrication,low cost,high sensitivity and large measurement range,which shows certain application potential in temperature monitoring fields.

国家自然科学基金(61805197)、陕西省科技成果转移与推广计划(2021CGBX-38)和西安石油大学研究生创新与实践能力培养计划项目(YCS20111010)资助项目