High-speed large-dynamic-range fiber bragg grating demodulation system and method

Abstract

The invention discloses a high-speed large-dynamic-range fiber bragg grating demodulation system, which comprises a broadband light source, a three-port optical fiber circulator, an optical fiber coupler with a splitting ratio of 50:50, a first narrow-band filter, a second narrow-band filter, a first photoelectric detector, a second photoelectric detector and a data acquisition and processing unit, wherein the output spectrum of the broadband light source is in a Gaussian type with a linear long hypotenuse, the spectrum has unimodality, high-speed demodulation of the fiber bragg grating is carried out by utilizing left and right approximately linear long hypotenuses in the output spectrum of the broadband light source, and the wavelength change of the grating is converted into the change of the power of reflected light output by the grating. The invention further provides a method for demodulating a fiber bragg grating sensor by using the high-speed large-dynamic-range fiber bragg grating demodulation system. The demodulation system has the advantages of high demodulation speed, wide measurement range, high demodulation precision, small limitation on grating wavelength and the like, and is suitable for testing transient large variables such as explosive shock wave pressure.

Description

technical field [0001] The invention relates to optical fiber sensing technology, in particular to a fiber grating demodulation system and demodulation method with high speed and large dynamic range. Background technique [0002] The measurement of explosion shock wave pressure has always been a very important issue in the research of weapon explosion engineering effects and engineering protection scientific research experiments. Due to the harsh explosion environment, there are not only few types of sensors available for explosion shock wave pressure measurement, but also the sensors in these optional ranges have disadvantages such as poor anti-interference ability and less adaptability to occasions. In recent years, the introduction of optical fiber sensing technology into the field of explosion effect parameter measurement to develop an optical fiber shock wave pressure sensor provides a new method for explosion shock wave pressure measurement. Among them, the explosion ...

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Problems solved by technology

At present, the linear wavelength-dependent components commonly used in fiber Bragg grating demodulation mainly adopt the hypotenuse filter scheme, such as the near-linear hypotenuse on the transmission spectrum or reflection spectrum of fiber F-P interferometer, long-period fiber grating, wavelength division multiplexer, etc. , although it can achieve a high demodulation speed, it is limited by the small linear wavelength range of the filter element, which generally does not exceed 3nm, resulting in a small measurement range; affected by the stability of the filter element, the calibration sensitivity of the sensor is unstable , the demodulation accuracy is not high

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