A corrugated surface long period grating (LPG) imprinted on a plastic optical fiber (POF) was proposed as a liquid level sensor. The LPG was fabricated by a simple mechanical die-press-print method. The operation principle of the sensor was analyzed by the method of geometrical optics. The liquid-level sensing performances of the sensor with different structural parameters were evaluated. The results showed that the diameter of POF and the structure parameters of LPG would affect the liquid level sensing performance. When the LPG with a period of 300 µm, a groove depth of 75 µm, and a tilted angle of 30° was fabricated on a POF with a diameter of 0.25 mm, the highest sensitivity of − 0.4381 dB/mm was obtained in the water-level range of 20 mm. The calculated results nearly coincided with the measured results. The hysteresis of the proposed sensor performed well and the sensitivity of the sensor was increased when the liquid RI was increased. Moreover, the water absorption would influence the liquid level sensing performance when the LPG was immersed in the water for a long time.

建议将压印在塑料光纤 (POF) 上的波纹表面长周期光栅 (LPG) 作为液位传感器。LPG 是通过简单的机械模压印刷方法制造的。采用几何光学方法分析了传感器的工作原理。评估了具有不同结构参数的传感器的液位传感性能。结果表明，POF的直径和LPG的结构参数会影响液位传感性能。当在直径为 0.25 mm 的 POF 上制作周期为 300 µm、凹槽深度为 75 µm、倾斜角为 30°的 LPG 时，在水中获得的最高灵敏度为 - 0.4381 dB/mm - 水平范围为 20 毫米。计算结果与实测结果几乎一致。所提出的传感器的滞后表现良好，当液体 RI 增加时，传感器的灵敏度也增加。此外，当液化石油气长时间浸入水中时，吸水率会影响液位传感性能。