Lin Weihao, Zhao Fang, Hu Jie, Liu Yuhui, Xu Renan, Chen Xingwei, Shao Liyang
The Higher Educational Key Laboratory for Flexible Manufacturing Equipment Integration of Fujian Province, Xiamen Institute of Technology, Xiamen 361021, China.
School of Mechanical Electrical and Information Engineering, Xiamen Institute of Technology, Xiamen 361021, China.
Sensors (Basel). 2024 Aug 18;24(16):5339. doi: 10.3390/s24165339.
A novel demodulation scheme for a point-type fiber sensor is designed for salinity concentration monitoring based on a Sagnac interferometer (SI) composed of a tapered polarization-maintaining fiber (TPMF) and optical time stretching technology. The SI, constructed using a PMF with a taper region of 5.92 μm and an overall length of 30 cm, demonstrated a notable enhancement in the evanescent field, which intensifies the interaction between the light field and external salinity. This enhancement allows for a direct assessment of salinity concentration changes by analyzing the variations in the SI reflection spectra and the experimental results indicate that the sensitivity of the sensor is 0.151 nm/‱. In contrast to traditional fiber optic sensors that depend on spectral demodulation with slower response rates, this work introduces a new approach where the spectral shift is translated to the time domain, utilizing a dispersion compensation fiber (DCF) with the demodulation rate reaching up to 50 MHz. The experimental outcomes reveal that the sensor exhibits a sensitivity of -0.15 ns/‱ in the time domain. The designed sensor is anticipated to play a pivotal role in remote, real-time monitoring of ocean salinity.
基于由锥形保偏光纤（TPMF）和光时域拉伸技术组成的萨格纳克干涉仪（SI），设计了一种用于盐度浓度监测的点型光纤传感器的新型解调方案。该SI由一段锥度区域为5.92μm、总长度为30cm的保偏光纤构建而成，其倏逝场有显著增强，这强化了光场与外部盐度之间的相互作用。这种增强使得通过分析SI反射光谱的变化能够直接评估盐度浓度变化，实验结果表明该传感器的灵敏度为0.151nm/‱。与传统依赖较慢响应速率的光谱解调的光纤传感器不同，这项工作引入了一种新方法，即将光谱偏移转换到时域，利用色散补偿光纤（DCF），解调速率高达50MHz。实验结果表明，该传感器在时域中的灵敏度为-0.15ns/‱。预计所设计的传感器将在海洋盐度的远程实时监测中发挥关键作用。
