Sensing device for eliminating temperature sensitive current of FBG (Fiber Bragg Grating) cascaded optical fiber composite structure

Abstract

The invention provides a sensing device for eliminating temperature sensitive current of an FBG cascade optical fiber composite structure. The sensing device comprises an ASE (1), a circulator (2), a measuring system (3), a spectrum analyzer (4), demodulation software (5) and a computer (6). According to the invention, a Mach-Zehnder interferometer principle and an FBG sensing principle are adopted. A light beam generated by the ASE generates an interference spectrum in a Mach-Zehnder interferometer formed by welding the optical fiber bag, the photonic crystal fiber and the tapering multimode fiber, temperature measurement is realized through detection of the interference spectrum, and current measurement is realized through a reflection peak generated by the FBG, detection of changes of a magnetic field generated by current and detection of the magnetic field generated by the current. And eliminating the influence of the temperature by using an analysis matrix. According to the invention, the detection for eliminating temperature-sensitive current is realized, the detection error is small, the current can be output on a computer, and the current real-time monitoring for eliminating temperature influence is realized.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to an FBG cascaded optical fiber composite structure eliminating temperature sensitive current sensing device. Background technique [0002] Compared with traditional electronic sensors, optical fiber sensors have higher sensitivity, remote measurement, no electromagnetic interference, small size, and can be used in harsh environments such as high pressure, high temperature, and corrosion. The computer connection has high flexibility and usability. At present, researchers have developed many optical fiber sensors, which can measure parameters such as temperature, stress, and pressure. With the continuous increase of social needs, the demand for multifunctional and small sensors is gradually expanding. Design a fiber optic composite structure based on ethanol chloroform and GMM material, which can realize the dual-parameter measurement of temperature and ma...

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Problems solved by technology

For example: In 2019, Zhang R et al. (Zhang R, Pu S, Li Y, et al. Mach-Zehnder interferometer cascaded with FBG for simultaneous measurement of magnetic field and temperature [J]. IEEE Sensors Journal, 2019, 19(11): 4079-4083.) proposed an optical sensor that cascades the FBG and the MZI of the upper conical structure to measure the dual parameters of temperature and magnetic field, in which the MZI structure is immersed in the magnetic fluid environment to realize magnetic field sensing, and the FBG structure realizes temperature measurement. However, because the magnetic fluid is easy to demagnetize, the life of the material is short, and the life of the sensor is reduced; J] ".AppliedOptics,2020,59:1-9) use photonic crystal fiber to manufacture Mach-Zehnder interferometer, and realize dual-parameter measurement of temperature and humidity by filling alcohol and coating Go through photonic crystal fiber. Although the dual-parameter measurement is realized, the manufacturing process is complicated, which is not as simple as the cascade structure, and the alcohol in the photonic crystal fiber is volatile, which leads to the short life of the sensor and low measurement sensitivity; in 2019, Lei X Q et al. (Lei X Q, Feng Y, Dong X P. High-temperature sensor based on a special thin-diameter fiber [J]. Optics Communications, 2020, 463: 125386.) Proposed based on a special thin-diameter fiber sandwiched between two sections of multimode fiber, with two A section of multimode fiber is used as a coupler to make an all-fiber Mach-Zehnder interferometer for temperature measurement. This device is simple to make and has the advantages of repeatability and low cost, but this device can only measure temperatures above 100 degrees Celsius. The measurement sensitivity of temperature is low; in 2021, Ye Chuni et al. (Ye Chuni, Chen Heming. Photonic crystal fiber temperature sensor based on surface plasmon resonance [J / OL]. Optical communication technology) used chloroform mixed with alcohol to study the temperature of ethanol chloroform at different temperatures The refractive index of the mixed liquid has verified that the ethanol-chloroform mixed liquid makes the sensor have better sensitivity, but the production of the photonic crystal fiber is relatively complicated, and no dual-parameter measurement has been performed; in 2020, Tong R et al. (Tong R, Zhao Y, Hu H, etal.Large measurement range and high sensitivity temperature sensor with FBGcascaded Mach-Zehnder interferometer[J].Optics&Laser Technology,2020,125:106034.) FBG and MZI cascaded to design a large-range detection fiber optic temperature sensor, which uses a single MZI is formed by dislocation fusion splicing of mode fiber, and the temperature-sensitive material polydimethylsiloxane (PDMS) is coated on the dislocation fusion zone, FBG is used to judge the temperature, and MZI is used to achieve accurate temperature reading; in 2020, Xia F et al. ( Xia F, Zhao Y, Zheng H, et al.Ultra-sensitive seawater temperature sensor using an FBG-cascaded microfiber MZIoperating at dispersion turning point[J].Optics&Laser Technology,2020,132:106458.) proposed a seawater temperature detection method Optical fiber sensor, which uses FBG and micro-nano optical fiber cascade structure to realize temperature detection, in which the surface of micro-nano optical fiber is coated with PDMS temperature-sensitive material to generate MZI. The cascaded structure enhances the sensitivity and detection range. Although the sensing unit realizes temperature control Wide detection range, but the structure is complex, and only parameter measurement can be realized; in 2021, Zhan B et al. (Zhan B, Ning T, Pei L, et al. J].IEEE Access,2021,9:32713-32720.) proposed to paste two FBGs on Terfenol-D material according to different angles to realize a temperature-compensated magnetic field sensor. This sensor only realizes parameter measurement, but the demodulation structure is complicated

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