Study On Solution Concentration Measurement Technology Based On Optical Fiber

Concentration is one of the important parameters for characterizing the solutionproperties, particularly in the real-time detection of chemical, environmental, andsugar concentration. The fiber optic sensor is a new technology along with thedevelopment of optical fiber communication appears. Its immunity to electromagneticinterference, flexibility, and high sensitivity, corrosion resistance, ease of telemetry, asimple structure, low power consumption, etc., can compensate for the deficiencies ofthe traditional concentration detection means. Especially in the field of detection ofcorrosive solution, it has a good prospect.In this thesis, the theoretical analysis and experimental study of the fiber liquidconcentration detection technology has been discussed. The main contents include:Combined with the research status, analyze the progress of concentration detectiontechnology and optical concentration detection technology; Describe the process andthe laws of the waveguide transmission in fiber; By the fresnel formula, analyze therelationship between reflection and refraction of light propagation in the medium; andexpound the principle of concentration detection system; Analysis and experimentalstudy of the corrosion and production process of the sensing fiber, The experimentused concentration of40%hydrofluoric acid corrosion of fiber; By measurement theoptical fiber diameter of corrosion different times, obtain a linear relationship betweenthe etching time and fiber diameter; Build a fiber concentration detection system, anduse this system for the measurement experiment of three different diameter of thesensing fiber on the concentration of sucrose solution, the experimental relationship ofthe optical power loss and concentration is given; Research drawn: as the solutionconcentration increases(refractive index increase), the optical fiber transmitted lightdecreases, the intensity loss gradually become larger, consistent with the theoreticalanalysis, the diameter of the sensing fiber has a different sensitivity to changes inconcentration, that is, the smaller the diameter, the higher the sensitivity.