This paper shows a new fiber optic sensor multiplexed system for liquid level sensing. Biconical fiber tapers converging at a 40 mm-long micro-fiber are used as transducers. The tapers are designed to provide the propagation of the two main cylindrical modes in the micro-fiber avoiding higher order modes or modes with other symmetries. The liquid level is calculated in real time from the measurement of the frequency and phase components of the spectral interference pattern of the submerged micro-fiber. The system is fully characterized by theoretical simulations in terms of the sensitivity as a function of the most responsive parameter, which is the width of the micro-fiber. Phase sensibilities of 3.7 rad/mm are experimentally obtained and values as high as 11.4 rad/mm are theoretically predicted. The strong dependence of the spatial frequency with the width of the micro-fiber has been used to multiplex three sensors in series in this domain. The maximum detected crosstalk between sensors is 0.2 rad/mm.

本文展示了一种用于液位传感的新型光纤传感器多路复用系统。会聚在40毫米长的微纤维上的双圆锥光纤锥度用作换能器。锥度被设计为在超细纤维中提供两个主要的圆柱模的传播，从而避免了更高阶的模或具有其他对称性的模。液位由浸入式微纤维的光谱干涉图样的频率和相位分量的测量值实时计算得出。该系统通过理论模拟完全表征为灵敏度，该灵敏度是最敏感的参数（即微纤维的宽度）的函数。通过实验获得了3.7 rad / mm的相敏度，理论上预测了高达11.4 rad / mm的相敏度。空间频率与微纤维宽度的强烈相关性已被用于在此域中多路复用串联的三个传感器。传感器之间检测到的最大串扰为0.2 rad / mm。