一种腐蚀增敏光纤迈克尔逊干涉型折射率传感器

A Corrosion Enhancing Optical Fiber Michelson Interference Type Refractive Index Sensor

摘要: 本文利用细芯光纤(TCF)并基于迈克尔逊干涉原理制备了折射率传感器。该传感器采用两段单模光纤(SMF)中间熔融一段细芯光纤，形成迈克尔逊干涉结构。该结构由于单模与细芯光纤的纤芯不匹配，使得在第1个熔接点处激发出包层模式，并在第2个熔接点处与纤芯模耦合发生干涉，实验结果显示随着折射率的增加干涉条纹发生蓝移。接着我们为了增强传感器的灵敏度又对细芯光纤进行腐蚀，腐蚀之后与之前相比发现，在低折射率条件下，折射率与波长变化呈现很好线性关系，对比腐蚀前传感器性能有了很大的提高。实验最终结果显示，在高折射率区1.42~1.4435范围内，折射率在长波长处最高达到−564.09 nm/RIU，并且第二、三和四个波段处灵敏度与未腐蚀前相比分别提高了0.9655、0.71和0.7倍。

Abstract: In this paper, a refractive index sensor based on Michelson interference principle is fabricated by using thin-core fiber (TCF). The sensor uses a two-stage single-mode fiber (SMF) in the middle of melting a thin-core fiber to form Michelson interference structure. The cladding mode is excited at the first fusion point and the interference occurs at the second fusion point. The experimental results show that with the increase of the intensity of the core, the increase of the refractive index causes the interference fringe to be blue-shifted. Then, in order to enhance the sensitivity of the sensor, we have corroded the thin-core fiber . After the etching, it is found that under the low refractive index, the refractive index has a good linear relationship with the wavelength. Compared with the pre-corrosion sensor, the sensor performance which after the corrosion has been greatly improved. The experimental results show that the refractive index reaches -564.09 nm/RIU at the long wavelength in the high refractive index region of 1.42-1.4435, and the sensitivity at the second, third and fourth bands was increased by 0.9655, 0.71 and 0.7 times, respectively, compared with that before the non-etching.