针对当前光纤法布里-珀罗(F-P)传感器解调仪存在的结构复杂和成本较高等问题, 提出一种基于光学相关原理的新型解调方案.采用平板玻璃作为光学互相关器, 利用平板玻璃与F-P腔的互相关关系解调出光纤F-P传感器的腔长.建立仿真模型对解调光路进行优化设计, 搭建了结构简单的单模光纤F-P传感器解调仪, 该仪器仅由宽谱光源、平板玻璃、线阵CCD、柱面镜和单模光纤搭建而成.实验结果表明, 腔长解调分辨率达到0.72 nm.该解调仪在光纤测井、液位测量和结构健康监测等领域中的温度、压力和位移测量中有着广阔的应用前景.

In view of the complicated structure and high cost of the ever reported fiber-optic Fabry-Perot (F-P) sensing demodulator, a new demodulation scheme based on optical correlation is presented in this paper. A glass wafer is used as an optical cross-correlator. The cavity length of the F-P sensor is demodulated by the cross-correlation relationship between the glass wafer and the F-P cavity. To optimize the optical path, the single-mode fiber-optic F-P sensing demodulator with a simple structure has been constructed by establishing a simulation model. The demodulator consists of a broadband light source with the center wavelength of 850 nm, a glass wafer, a linear CCD, a cylindrical mirror and a single-mode fiber. Experimental results show that the resolution of the demodulated cavity length is achieved to be 0.72 nm. The proposed demodulator has broad prospects in the fields of well logging, liquid level monitoring and structural health monitoring for temperature, pressure and displacement measurements.