PSD-based fiber bragg grating vibration sensor demodulation system and method

Abstract

The invention provides a PSD-based fiber bragg grating vibration sensor demodulation system and method. The system comprises a fiber bragg grating vibration sensor, a broadband light source, a circulator, a collimator, a one-dimensional PSD, a focusing lens, a diffraction grating, and a processing circuit. Broadband light emitted by a broadband light source passes through the circulator and then enters the fiber bragg grating vibration sensor. Reflected light output by the grating vibration sensor passes through the circulator and then enters the collimator, light beams are converted into collimated light beams and then are irradiated to the diffraction grating, the propagation angles of light with different wavelengths are changed after the light beams pass through the diffraction grating, and the light beams are irradiated to the photosensitive surface of the one-dimensional PSD after being focused and adjusted by the focusing lens. The positions of the light with different wavelengths irradiated on the photosensitive surface of the one-dimensional PSD are different so that the one-dimensional PSD outputs different current signals, and the processing circuit converts the currentsignals output by the one-dimensional PSD into voltage signals and performs amplification and filtering. The demodulation system and method provided by the invention have the characteristics of high precision and high-speed response, and have wide application prospects.

Description

Technical field [0001] The present invention belongs to the field of fiber sensing technology, and in particular, the present invention relates to a PSD (position sensitive detector) based fiber grating vibration sensor demodulation system and method. Background technique [0002] The fiber-optic grating vibration sensor is an emerging vibration measurement means for use in the measurement of vibration, impact, pulsating pressure, and sound signal. The fiber-optic grating vibration sensor has the characteristics of strong anti-electromagnetic interference ability, good electromagnetic isolation, essential explosion, high transmission distance, and strong environmental adaptability, it is ideal for high precision in strong electricity, strong magnetic, ray radiation, extreme high and low temperature environment. Measurement, currently, fiber optic grating vibration sensors have been widely used in aerospace, nuclear industry, petrochemical, civil buildings and other fields. [000...

AI Technical Summary

Problems solved by technology

[0003] The demodulation method of the fiber grating vibration sensor includes intensity demodulation and wavelength demodulation. The intensity demodulation can achieve a high demodulation speed, but it is very susceptible to the fluctuation of light intensity, the disturbance of optical cable and the drift of optical device parameters. The measurement The accuracy is not high, which limits its engineering application; wavelength demodulation has high measurement accuracy and is not affected by light intensity fluctuations, but the measurement speed is low, and the measurement speed generally depends on the scanning speed of the scanning laser or the data reading speed of the linear detection array

IBSEN's IMON series modules, which are widely used at present, have a wavelength demodulation speed of up to 34KHz, and can only collect signals less than 10KHz in engineering. However, the wavelength demodulation speed of the current product still cannot meet the engineering needs, which limits the fiber grating Applications of vibration sensors

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