U-shaped structure sapphire fiber grating temperature and stress sensor and manufacturing method thereof

Abstract

The invention discloses a U-shaped structure sapphire fiber grating temperature and stress sensor and a manufacturing method thereof. According to the U-shaped structure sapphire fiber grating temperature and stress sensor, the end face of a section of sapphire fiber is of a micropore structure, and a low-refractive-index cladding structure similar to photonic crystal fiber is formed; a section of long-period fiber grating enables MgO to be doped on the side face of the fiber by the adoption of an electromagnetic sputtering method so as to form MgAl2O4 crystals through reaction, the mechanical strength of the section of the fiber is changed, after grating is written into the fiber, two sections of grating are different in stress response, and the effect that temperature and stress are measured at the same time can be achieved. The U-shaped structure sapphire fiber grating temperature and stress sensor has the advantages of being simple in structure, wide in temperature measuring range, high in measuring accuracy and the like, and can be applied to temperature and stress measurement of rocket engines, optical cowlings and ultra-high temperature environments.

Description

Technical field: [0001] The invention relates to an optical fiber sensor device in the field of optical fiber, in particular to a U-shaped structure optical fiber grating temperature stress sensor capable of simultaneously measuring dual parameters of temperature and stress and a preparation method thereof. Background technique: [0002] Fiber Bragg Grating sensors have attracted widespread attention due to their advantages such as simple structure, electrical insulation, anti-electromagnetic interference and resistance to harsh environments. Simultaneous sensing of temperature and stress is currently a hotspot in the study of FBG sensing, but FBG is sensitive to temperature and stress at the same time, that is, both temperature and stress can cause FBG peak wavelength sensitivity. Therefore, the key to simultaneously realize the sensing of temperature and stress is to solve the problem of cross-sensitivity of temperature and stress. [0003] People have done a lot of resea...

AI Technical Summary

Problems solved by technology

This solution solves the problem that the two gratings need to be coupled, but it is difficult to ensure the adhesion between the fiber grating and the metal in ultra-high temperature, so the measurement in a specific environment is limited

[0005] In addition, Stephen.J.Mihailov et al. used the response of the peak wavelength of the fiber Bragg grating to temperature and stress, put the fiber Bragg grating into a micro furnace, and realized the measurement of temperature and stress respectively. This method achieved a temperature measurement value of 1290 ° C, but This method cannot realize the simultaneous measurement of temperature stress, and the single-mode transmission in sapphire fiber is difficult to control. This is a report on the use of sapphire fiber for high temperature stress sensing

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