Liquid level sensor system based on monomode -multimode-monomode optical fiber structure and Bragg gratings

Abstract

A liquid level sensor system based on a monomode-multimode-monomode optical fiber structure and Bragg gratings comprises an electric linear platform, a temperature control platform, a water container, an optical fiber group, a circulator, a broadband light source and a spectrograph. The optical fiber group comprises first monomode optical fibers, second monomode optical fibers, multimode optical fibers and the Bragg gratings etched on the second monomode optical fibers, and is fixed vertically according to the sequence of the first monomode optical fibers, the multimode optical fibers and the second monomode optical fibers. The optical fiber group is soaked in the water container. The electric linear platform is connected with the optical fiber group through a support. The water container is arranged on the temperature platform. The optical fiber group is connected with the circulator. The circulator is connected with the broadband light source and the spectrograph clockwise. The liquid level sensor system has the advantages that the central wavelength of the Bragg gratings is positioned in a filter spectrum area at the edge of a sensor, and a Bragg grating reflection spectrogram is determined to measure the liquid level, so that operability and sensitivity are high, structure is simple and loss is low.

Description

technical field [0001] The invention relates to a liquid level sensor, in particular to a liquid level sensor system based on a single-mode-multimode-single-mode optical fiber structure and a Bragg grating, belonging to the technical field of optical fiber sensing. Background technique [0002] Today, liquid level sensing is becoming increasingly important in many applications such as fuel storage, liquid quantitative and qualitative monitoring, and chemical processing. Various traditional mechanical or electrical methods can be used to detect liquid level, including float, ultrasonic, magnetic Scaling, differential pressure and capacitive methods, etc. However, the above methods have several disadvantages, such as high maintenance cost, susceptibility to electromagnetic interference, complex structure and low resolution, etc. At the same time, if the liquid to be measured is conductive, erosive or even potentially explosive, its application is limited. may be damaged. [...

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Problems solved by technology

[0004] Patent CN 203981244 U discloses a liquid level sensor based on a thin-core tilted fiber grating, which can accurately measure the change of the liquid level by changing the reflection spectrum of the thin-core tilted fiber grating, but the measured liquid The material is limited by temperature, and there are certain limitations for some liquids that cannot be measured at room temperature, and the method of dislocation and docking of the fiber core is not used to obtain the grating reflection spectrum, so the cladding mode reflection spectrum is not easy to obtain

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