Air relative humidity measuring instrument based on inclined optical fiber grating

Abstract

The present invention discloses an inclined optical fiber raster based relative hygrometer for measuring relative humidity of air, which comprises a light source, single mode optical fibers, and an inclined optical fiber raster and an optical spectrum analyzer, wherein, the light source is connected through a single mode optical fiber to the inclined optical fiber raster, the output end of the inclined optical fiber raster is connected through a single mode optical fiber to the optical spectrum analyzer, and the inclined optical fiber raster is coated with a film made of a moisture sensitive material. The humidity sensitive material is polyimide material, or carbon-fiber composite material, or epoxy-phenolic resin moisture-sensitive material. The present invention incorporates the advantages of high moisture expansion linearity and stable chemical property of polyimide PI film, flexible design, high long term stability and exchangeability, and high response rate. In addition, the hightemperature resistant, corrosion resistant, and optical fiber raster type sensor incorporates high measuring accuracy, miniature, interference resistance, and reusability, and is suitable for use in environmental extremes. Therefore, the present invention has advantages including low cost, simple construction, and easy implementation.

Description

technical field [0001] The invention relates to an air relative humidity measuring instrument. In particular, it relates to an air relative humidity measuring instrument based on an inclined optical fiber grating, which uses an inclined optical fiber grating coated with a moisture-sensitive material as a sensing device to sense the external environment. Background technique [0002] Fiber Bragg Grating is a new type of photonic device, which is a spatially periodic refractive index distribution established in the optical fiber, which can change and control the propagation behavior of light in the optical fiber. Slanted fiber gratings use a special writing method to write a grating at a certain angle to the fiber axis in the core of the fiber, which can couple light in a specific wavelength range from the fiber core to the fiber cladding. Moreover, the tilted fiber grating is a short-period fiber grating whose grating surface has a certain tilt angle relative to the fiber ax...

AI Technical Summary

Problems solved by technology

At present, there is no solution for sensing and analyzing signals such as air relative humidity using tilted fiber grating sensors

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