A Method for Determining Fiber Bragg Resonance Wavelength Based on Periodic Modulation

A technology of Bragg resonance and fiber grating, applied in the direction of using optical devices, using optical devices to transmit sensing components, instruments, etc., to achieve the effect of improving demodulation accuracy

A technology of Bragg resonance and fiber grating, applied in the direction of using optical devices, using optical devices to transmit sensing components, instruments, etc., to achieve the effect of improving demodulation accuracy

CN107907067BActive Publication Date: 2020-04-10宁波核芯光电科技有限公司
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  • A Method for Determining Fiber Bragg Resonance Wavelength Based on Periodic Modulation
  • A Method for Determining Fiber Bragg Resonance Wavelength Based on Periodic Modulation
  • A Method for Determining Fiber Bragg Resonance Wavelength Based on Periodic Modulation

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Embodiment Construction

[0025] Embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0026] Such as figure 2 Shown is a schematic diagram of a demodulation device for obtaining periodic FBG reflection spectra. The strain needed to be obtained in the periodic modulation-based fiber Bragg resonance wavelength determination method of the present invention can be provided by the device or a device with an equivalent function to the device. by figure 1 The shown device is taken as an example. The vibration exciter is used to apply a periodic strain to the cantilever beam, and the frequency and amplitude of the vibration of the exciter are controlled by a signal generator and a power amplifier. Here, the frequency of the exciter is 1HZ, and the amplitude is 5V. , the frequency of the scanning light source is 400HZ as an example to describe this method in detail. The structure of the device and its working process are described in...

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Abstract

The invention discloses a fiber grating Bragg resonance wavelength determination method based on period modulation. According to the invention, by imposing periodical strain on a cantilever beam, a periodically changed reflection spectrum is obtained; by carrying out Fourier transform on curves of change of an intensity value at each wavelength point of each spectrum along with the modulation time, the specific value of second harmonic generation components and fundamental components therein is solved; by use of the specific value at each wavelength point, the spectrum of narrowing down of half-height is reconstructed, so the position of a peak point of the fiber grating reflection spectrum is quite precisely acquired; and high precision demodulation of the fiber grating is achieved. Compared with the prior art, the spectrum of narrowing down of half-height is reconstructed finally, and demodulation precision is further improved.

Description

technical field [0001] The invention relates to the field of optical fiber sensing, in particular to a method for accurately determining the Bragg resonance wavelength of an optical fiber grating based on periodic modulation. Background technique [0002] Fiber Bragg Grating (FBG) sensors are widely used in many fields due to their advantages of small size, light weight, strong anti-electromagnetic interference and easy modulation. The demodulation of the fiber grating sensor adopts wavelength coding, which makes the demodulation of the fiber grating free from the fluctuation of the light intensity of the light source and the loss caused by other devices, and has become the most widely used demodulation technology. FBG obtains changes in parameters such as temperature, vibration, dynamic and static strain, etc. by demodulating wavelength information. The common demodulation methods are: spectrum method, edge filter method, interference method, tunable narrowband light sourc...

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Application Information

Patent Timeline
10 Apr 2020
Publication
CN107907067B
IPC
G01B11/16; G01D5/353
CPC
G01B11/18; G01D5/35316
Inventors
张学智; 刘铁根