Abstract The Michelson liquid-level sensor based on silver coated the end face of the three-core fiber reflection structure has been proposed to measure continuous or discrete liquid level. The Michelson interference structure can be obtained by the combination of the single-mode optical fiber and the three-core optical fiber with the silver film coated on the other end face of it. The inter-mode interference can be obtained by the fiber-core mismatch at the fusion joint. The liquid level can be measured by monitoring the dip wavelength shift of the interference spectrum. The results indicate that the sensitivity of the liquid-level sensor will decrease with the increasing sensing length. The sensing length of 30 mm is selected to investigate the performance of the sensor. The sensitivity of water level is reached as high as 392.83 pm/mm with an excellent linearity of 0.99946. Interestingly, the sensitivity of the sensor increases with the liquid refractive index and the sensitivity of the refractive index for NaCl solution is 4410.74 pm/mm/RIU. The performance of the sensor is very stable in the range of 20–90 °C. The maximum drift for temperature is 0.3001 nm. The sensor can be applied to the measurement of the liquid level in different environments.

中文翻译：

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用于液位测量的镀银三芯光纤迈克尔逊干涉仪

摘要 提出了一种基于三芯光纤反射结构端面镀银的迈克尔逊液位传感器来测量连续或离散的液位。迈克尔逊干涉结构可以通过单模光纤和三芯光纤的组合得到，其另一端面涂有银膜。模间干扰可以通过熔接处的纤芯失配获得。液位可以通过监测干涉光谱的倾角位移来测量。结果表明，液位传感器的灵敏度会随着传感长度的增加而降低。选择 30 mm 的传感长度来研究传感器的性能。水位灵敏度高达392。83 pm/mm，具有 0.99946 的出色线性度。有趣的是，传感器的灵敏度随着液体折射率的增加而增加，NaCl 溶液的折射率灵敏度为 4410.74 pm/mm/RIU。传感器的性能在20-90°C范围内非常稳定。温度的最大漂移为 0.3001 nm。该传感器可应用于不同环境下的液位测量。