基于无芯光纤强度调制型液位传感器的设计与性能

利用强度调制型光纤传感器容易解调的优势,提出了一种强度调制型光纤液位传感器.传感器由三根无芯光纤组成,其中,无芯光纤1与无芯光纤2串联构成测量臂,无芯光纤3构成参考臂.仿真分析得出,无芯光纤长度每缩短1mm,透射峰波长增加25.46nm.在0~50mm小液位范围内,实验测得传感器在水、5%NaCl、10%NaCl和15%NaCl水溶液四种液体环境中的液位灵敏度分别为0.069 5dB/mm、0.074 73dB/mm、0.077 49dB/mm及0.082 71dB/mm,线性度分别为0.998 25、0.998 49、0.988 11及0.995 13,线性度较高.该传感器可较好地消除光源光功率波动与环境温度变化带来的影响,重复性较好,在石油化工领域有一定的应用潜力.

Design and Performance of Intensity Modulated Liquid-level Sensor Based on No-core Optical Fibers

In order to take advantage of the ease of demodulation of the intensity-modulated fiber-optic sensor,an intensity-modulated liquid level sensor is proposed.The sensor consists of three no-core optical fibers.Among them,the no-core fiber 1 and no-core fiber 2 are cascaded to form a measuring arm,and no-core fiber 3 constitutes a reference arm.The simulation analysis show that if the length of no-core fiber is shortened by 1 mm,the transmission peak wavelength is increased by 25.46 nm.In the 0~50 mm liquid level range,the measured sensitivities of the sensor in the liquid environments,namely water,5%NaCl,10% NaCl and 15% NaCl aqueous solutions, are 0.069 5 dB/mm,0.074 73 dB/mm,0.077 49 dB/mm and 0.082 71 dB/mm,respectively.The linearities of the sensor are 0.998 25,0.998 49,0.988 11 and 0.995 13,respectively.The proposed sensor can eliminate the influence of optical power fluctuation and ambient temperature variation with good repetition,and maybe has a potential application in the petrochemical industry.