Quick response type fiber bragg grating humidity sensor system and application method thereof

Abstract

The invention relates to a quick response type fiber bragg grating humidity sensor system and an application method thereof. The system comprises a light source, a wavelength division multiplexer andan FBG humidity sensor which are connected in sequence. The system also comprises a demodulation device connected to the wavelength division multiplexer. The system is characterized in that the powerrange of the output light of the light source is between 100mW and 2W, and the wavelength of the output light and the output wavelength of the light source in the demodulation device are staggered. The light source and the demodulation device are respectively connected to two different wavelength channels of the wavelength division multiplexer according to the wave bands of the output light of thelight source and the demodulation device. A common end of the wavelength division multiplexer is connected with the FBG humidity sensor through a section of transmission optical fiber. According to the invention, the response speed of the humidity sensor can be greatly improved, the system has the characteristics of electromagnetic interference resistance and safety, is suitable for rapid humidity measurement in a flammable, combustible and strong electromagnetic interference special environment, can carry out large-scale networking, and can also achieve a rapid response effect in a long distance.

Description

technical field [0001] The invention belongs to the field of optical fiber sensing and relates to a fast-response fiber Bragg grating (FBG) humidity sensor system. Background technique [0002] With the advancement of science and technology and the rapid development of industry and agriculture, the measurement of humidity has become more and more important. In the petrochemical industry, power industry, weapons and ammunition depots where there is strong electromagnetic interference and inflammable and explosive occasions, the existing electrical humidity sensors are prone to failure, and even cause safety accidents, resulting in huge irreparable losses. [0003] The fiber optic humidity sensor senses the humidity of the environment by detecting changes in the intensity, phase, and wavelength of light waves. It is intrinsically safe (electrically passive) and free from electromagnetic interference. As a member of the fiber optic sensor family, the fiber Bragg grating (refer...

AI Technical Summary

Problems solved by technology

However, regardless of the packaging method, the response speed of the FBG humidity sensor is inseparable from the moisture absorption / dehumidification speed of the humidity sensitive film

Although technically, the reaction time between the humidity-sensitive film and the water molecules in the environment can be reduced by reducing the thickness of the film or improving the performance of the polyimide material, the extent to which the response speed can be improved by these methods is limited, and these methods All rely on changing the physical and chemical parameters of optical fibers and moisture-sensitive coatings to increase the corresponding speed, and the means of realization are relatively simple

[0005] In addition, blindly reducing the thickness of the humidity-sensitive film will reduce the humidity sensitivity of the FBG humidity sensor

Therefore, the static response time of the general FBG humidity sensor is several minutes, or even more than tens of minutes, which is difficult to meet the dynamic monitoring requirements of the humidity environment.

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