The Research And Design Of Signal Processing Technology Of The Optical Fiber Displacement Sensor Based On Intensity Modulation

Optic fiber sensors have been widely spreaded in various iudustries in recent years. With the development of telecommunications industry, the application of the fiber increases rapidly, the research of optic fiber sensors attracts more and more attention. Optic fiber sensor can detect many physical quantities, how to construct a sensor network through the integration of different optic fiber sensors has become a potential research project. Due to its special characteristics, optic fiber sensors have some advantages that the traditional sensors don't have. Therefore, the research of optic fiber sensor is very significant.This article focus on the research of the intensity modulated optic fiber diaplacement sensor. First, the research status and the development trend of the optic fiber sensor is introduced. Then, the main parts of optic fiber sensor and the function of each part are explained.The basical classification ways of optic fiber sensor are discussed. The focus is to study the intensity modulated fiber optic sensor,including the detecting principle of displacement and the geometry analysis of the transmitting fiber. According to the relevant references, the intensity modulated function is defined, typical light intensity distribution are introduced. In the assumption of the uniform distribution of light intensity and the specular reflection, the mathematical model is set up .Through calculating, the mathematical expression of the intensity modulated function is figured out. Based on the function, the impact of the structural parameters of the fibers to the curve of the the intensity modulated function is infered, this result could provide theoretical support for the structure designing of the fiber probe.Finally, a method to detect the weak signal is proposed, analog devices are used to design the signal processing circuit, including bandpass filter, voltage regulator, drive cuicuit of light source and so on. The design of the bandpass filter and the drive cuicuit are explained. The simulation of the circuit and the result of the experiment show that the circuit could filter the noise effectively.