提出了一种基于纤芯偏移衰耗的全光纤迈克耳逊干涉型液位传感器。理论和实验结果表明,传感器的反射谱的条纹对比度受浸在被测液体中的干涉臂臂长影响,当液位变化0～30 mm,干涉条纹对比度变化约3 dB,在线性区其液位灵敏度约为0.84 dB/mm。此外该传感器对温度不敏感,在30°Ｃ～80°Ｃ范围内,且没有任何温度补偿情况下,被测液位误差小于1％。该液位传感器有很好的鲁棒性和重复性,制作工艺简单,成本低,在实际工业应用中具有广泛的应用前景。

An all-fiber liquid level sensor based on core-offset attenuator is proposed and demonstrated. The interference fringe is affected by the fraction of the length of the interferometeric arm that is surrounded by the liquid. The experiments show that for a liquid level variation of 30mm, the maximum difference of attenuation changes about 3dB. Also in the linear region, a sensitivity of 0.84dB/mm is achieved. For a temperature range from 30°Ｃ to 80°Ｃ, the measured liquid level fluctuates less than 1％ without any temperature compensation. The liquid level sensor reported in this paper appears is proved more robust and repeatable, and its ease of fabrication makes it a low cost alternative to existing fiber liquid level sensor.