High-precision optical fiber grating sensing detection structure based on radio frequency optical modulation

Abstract

The invention relates to a high-precision optical fiber grating sensing detection structure based on radio frequency optical modulation, which is characterized by comprising a wavelength-adjustable optical source, an optical coupler, a radio frequency optical modulator, a pulse optical modulator, a optical band pass filter, an optical amplifier, an optical circulator, an optical coupler, a photoelectric detector and an electronic processor in sequential connection, wherein the optical circulator is connected with an optical fiber. The high-precision optical fiber grating sensing detection structure has the advantages that: 1, because the radio frequency optical modulation is adopted for realizing the optical frequency shit so that the wavelength / frequency of the detected light is accurate to the level of an electronic oscillator, and the wavelength adjustable optical source can be added for expanding the wavelength / frequency moving range; 2, the optical incoherent detection can be conveniently added in the structure for improving the detection signal-to-noise ratio; and 3, the detection structure can adapt to various optical fiber grating arrays, such as optical fiber grating arrays with the characteristic that each grating in the optical fiber grating group can be low-reflectivity optical fiber grating with the same center frequency or different center frequencies.

Description

technical field [0001] The invention relates to optical fiber Bragg grating sensing and belongs to the technical field of optical fiber sensing. Background technique [0002] Due to the characteristics of high precision and strong anti-interference ability of fiber grating, it has been well developed at home and abroad. For example, patent CN1384341A discloses a fiber grating sensor for simultaneous detection of pressure and temperature, and patent 1904658A discloses a coherent multiplexing method and equipment for fiber Bragg grating sensors. These disclosures have introduced some fiber grating sensing methods very well, but they still have many limitations, such as the difficulty in realizing high-precision fiber grating measurement, especially the fiber grating detection method using a wavelength-tunable light source. Due to the tunable wavelength It is difficult for the light source to achieve accurate and fast light wavelength / frequency shift, which makes it difficult ...

AI Technical Summary

Problems solved by technology

These disclosures have introduced some fiber grating sensing methods very well, but they still have many limitations, such as the difficulty in realizing high-precision fiber grating measurement, especially the fiber grating detection method using a wavelength-tunable light source. Due to the tunable wavelength It is difficult for the light source to achieve precise and fast light wavelength / frequency shift, which makes it difficult for the fiber grating sensor using this solution to achieve high-precision and fast sensing and detection

Although the use of optical phase-locked light sources can obtain high-precision optical wavelength / frequency changes, the high technical difficulty and cost of its implementation are difficult to meet the needs of practical applications

[0003] Some domestic patents also disclose the method of FBG detection, such as CN2760526Y disclosed distributed FBG temperature detection system, one of its characteristics is to use tunable fiber filter to modulate the light source; CN101586986A discloses a high-precision FBG wavelength demodulator The system is characterized by the combination of optical filters and photodetectors; the optical fiber sensing wavelength tunable light source disclosed in CN201656245 combines multiple laser diodes with different center wavelengths and filters to produce a wavelength-tunable light source, but the accuracy is not high

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