Abstract

An all fiber Mach–Zehnder interferometric (MZI) sensor for measuring temperature and refractive index (RI) is proposed and experimentally demonstrated. The proposed sensor is fabricated with a coreless–few mode–coreless fiber structure. Variations in ambient temperature and RI cause changes in phase differences between the fundamental mode and the higher-order modes, leading to shifts in interference spectrum. The two resonance dips shifts within the wavelength spectrum are used to investigate the temperature and RI characteristics of the sensor. Experimental results show that the two dips have different responses to temperature and RI, indicating that the sensor can realize simultaneous measurement of temperature and RI; the maximum sensing sensitivities are 0.0739 nm/°C and −25.29 nm/RIU, respectively. The proposed sensor has potential applications in physical, biological, and chemical sensing owing to its low cost, good linearity, and simple fabrication.

摘要

提出并通过实验证明了一种用于测量温度和折射率 (RI) 的全光纤 Mach-Zehnder 干涉 (MZI) 传感器。所提出的传感器采用无芯-少模-无芯光纤结构制造。环境温度和 RI 的变化会导致基模和高阶模之间的相位差发生变化，从而导致干涉光谱发生偏移。波长谱内的两个共振倾角偏移用于研究传感器的温度和 RI 特性。实验结果表明，两个倾角对温度和折射率有不同的响应，说明该传感器可以实现温度和折射率的同时测量；最大传感灵敏度分别为 0.0739 nm/°C 和 −25.29 nm/RIU。