A fiber bragg grating transverse pressure transducer system based on a microwave photonic filter and a measuring method thereof

Abstract

The invention discloses a fiber bragg grating transverse pressure transducer system based on a microwave photonic filter and a measuring method thereof. The system comprises a broadband light source, an electro-optic intensity modulator, an optical fiber coupler, a fiber bragg grating, an optical fiber polarization beam splitter, an adjustable optical fiber delay line, an adjustable optical fiber attenuator, a chromatic dispersion compensation optical fiber, a photoelectric detector and a vector network analyzer. When the fiber bragg grating is subjected to the effect of a transverse pressure, two beams of optical signals with different center wavelengths will be reflected because of a birefringence effect. The two beams of optical signals are respectively corresponding to different polarization directions. When the transverse pressure changes, a center wavelength difference of the two beams of reflected light will change so as to change the resonant frequency of a microwave photonic notching filter. A frequency response curve of the filter is measured by the vector network analyzer to obtain the resonance center frequency to realize measurement of the transverse pressure. The fiber bragg grating transverse pressure transducer system of the invention is advantaged by being high in resolution, adjustable in sensitivity and capable of realizing long distance transverse pressure measurement in an electromagnetic interference preventing mode.

Description

technical field [0001] The invention belongs to the field of optical fiber sensing, in particular to a fiber Bragg grating transverse pressure sensing system based on a microwave photon filter and a measuring method thereof. Background technique [0002] Fiber Bragg grating sensor is an important wavelength modulation optical fiber sensor. The sensing process based on fiber Bragg grating is that when the fiber Bragg grating is affected by temperature and strain, its central wavelength will change linearly, so the information of physical parameters such as temperature and strain can be restored by detecting the movement of wavelength. Fiber Bragg grating sensors can be attached to the surface of the structure or pre-embedded in the structure, and can perform health detection, impact detection, and monitoring of structural defects at the same time. Compared with traditional electrical sensors, fiber Bragg grating sensors have attracted much attention due to their advantages s...

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Problems solved by technology

However, because the transverse pressure sensitivity of fiber Bragg gratings is very low, and the wavelength resolution of common spectrum analyzers is only a dozen pm, the tradi

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