Fiber bragg grating hydrogen sensor based on femtosecond laser micromachining and preparation method for fiber bragg grating hydrogen sensor

Abstract

The invention discloses a fiber bragg grating hydrogen sensor based on femtosecond laser micromachining and a preparation method for the fiber bragg grating hydrogen sensor. The method comprises the following steps of: preparing a straight slot array or an intersected helical slot three-dimensional micro structure on a fiber bragg grating wrapping layer through femtosecond laser, and plating a palladium alloy film, wherein the sensitivity of the sensor is greatly improved, and the service life of a thin film is prolonged. The fiber bragg grating hydrogen sensor is characterized in that a femtosecond laser micromachining technology is introduced; by a clamp, irregular micro pits are obtained by quickly scanning the wrapping layer; and the three-dimensional micro structure is prepared inside the grating wrapping layer. After the fiber bragg grating with the micro structure is plated with the film, a hydrogen absorption surface area is enlarged, and the axial direction of an optical fiber is softened; the grating wavelength drift is greatly improved by hydrogen absorption expanding strain; and therefore, the measuring precision is improved, and the measuring range is expanded. By the grating wrapping layer plated film with the surface micro pits and the bent three-dimensional micro structure, the adhesive force of the thin film can be greatly improved, and the service life of the thin film is prolonged. The sensor has the advantages of high sensitivity, wide measuring range, long service life and the like, and is suitable for remote monitoring.

Description

technical field [0001] The invention relates to a fiber grating hydrogen sensor based on femtosecond laser micromachining and a preparation method thereof. Specifically, it is an optical fiber optical hydrogen sensor based on femtosecond laser processing optical fiber microstructure, and then coating a hydrogen sensitive film and a preparation method thereof. Background technique [0002] Since the advent of fiber grating sensors, the stability of long-term, real-time and on-line monitoring of fiber grating sensing technology has been widely recognized by experts. And with its unique advantages, it has been widely used in bridges, railways, highway tunnels, petrochemical and other industries, and has developed rapidly. So far, improving the accuracy and sensitivity of fiber grating sensors is mainly achieved by using elastic diaphragms of different materials and shapes, optimizing the structure, applying pre-tightening force, and improving the packaging process. [0003] T...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a fiber grating hydrogen sensor based on femtosecond laser micromachining and its preparation method in order to overcome the technical defects of low sensitivity and short film life of the existing fiber grating hydrogen sensor

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