基于F-P腔和FBG的强度调制型光纤液位传感器

设计了一种用于液位测量的光纤F-P(Fabry-Perot)传感器,并从传感头的设计制作出发,讨论了提高传感器输出信号对比度的方法;测量系统采用宽带光源,解调时经FBG(Fiber Bragg Grating)反射和透射得到传感信号和参考信号,对两路光强信号进行联合处理,补偿了光源功率波动和光路损耗变化引起的不良影响,消除了强度调制型传感器的固有缺点,此方法具有结构简单、成本低的优点;该系统可进行连续测量,测量范围为0到200kPa,相当于测量水深0到20m,其分辨力小于1cm(水面高度变化),特别适合对易燃易爆的环境中的油库液位进行测量。

Optical fiber liquid level sensor based on F-P interferometer and FBG

We designed an intensity-modulated sensing system based on the F-P(Fabry-Perot) cavity interferometer and FBG(Fiber Bragg Grating) for liquid level.The sensor can be used to measure oil height of oil storage tanks.The system has the immunity from the drift of light source power and fluctuations in fiber attenuation by using a FBG.The sensor is interrogated by broadband light.FBG is used as a filter to obtain the sensing signal and reference signal,subsequently the two signals are processed at the same time.So the inherent disadvantage of intensity-modulated sensor is removed.And its key advantages are simple and low cost.The structure of the F-P interferometer sensor is presented.A method of fmding an optimal reflectivity of the endfaces and the original lengh of the F-P cavity is proposed,which can improve the performance of the F-P measuring system.The dynamic range of the sensor is from 0 to 200kPa,and the resolution reaches to 100Pa.