Great-angle tilted fiber bragg grating mechanical vibration sensing array and system

Abstract

The invention discloses a great-angle tilted fiber bragg grating mechanical vibration sensing array and a great-angle tilted fiber bragg grating mechanical vibration sensing system. The great-angle tilted fiber bragg grating mechanical vibration sensing array comprises an optical fiber core, and is characterized in that: the front section of the optical fiber core is provided with a 45-degree tilted fiber bragg grating, and the 45-degree tilted fiber bragg grating serves as a polarizer of a great-angle tilted fiber bragg grating vibration sensor; an included angle between tilted grating stripes of the tilted fiber bragg grating and an optical fiber cross section is 45 degrees; the middle section of the optical fiber core is provided with N great-angle tilted fiber bragg gratings, and N is a natural number greater than or equal to 1; grating stripes of the N great-angle tilted fiber bragg gratings are parallel to one another, and an included angle between the tilted grating stripes of each great-angle tilted fiber bragg grating and the optical fiber cross section ranges from 79 to 84 degrees; and the outer surface of an optical fiber cladding corresponding to each great-angle tilted fiber bragg grating is provided with an elastic membrane. The great-angle tilted fiber bragg grating mechanical vibration sensing array and the great-angle tilted fiber bragg grating mechanical vibration sensing system can be widely used in the fields of optical fiber perimeter and structural safety monitoring, landslide early warning and the like.

Description

technical field [0001] The invention relates to an optical fiber sensor, in particular to a mechanical vibration sensing array and system of an extremely inclined optical fiber grating. Background technique [0002] In many practical engineering applications, it is very important and necessary to measure various low-frequency / high-frequency vibrations. For example: monitoring of low-frequency vibration (generally 0.1Hz-10Hz) of bridges, dams, high-rise buildings, and large water turbine engines in construction projects, vibration in earthquake and ground fluctuation measurement and engineering geological exploration (generally 2Hz-50Hz) ) monitoring, underwater sound field (hundreds of Hz) and ultrasonic (>20kHz) detection in the military field, etc. [0003] At present, the existing vibration sensors can be divided into three categories according to the measurement methods of various parameters and the physical properties of the measurement process: mechanical, electric...

AI Technical Summary

Problems solved by technology

However, the current FBG-based vibration sensors basically use wavelength modulation, so interference is required to demodulate the rapid change of its resonance wavelength, although wavelength modulation and interferometric demodulation have very high measurement accuracy. Accuracy and sensitivity, but the requirements for interferometric demodulation are very high, such as the need to use unbalanced interferometric instruments, etc.

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