High-precision stress sensor based on Bragg fiber grating

A Bragg fiber and stress sensor technology, applied in the field of fiber optic sensors, can solve the problems of indeterminate frequency, unfavorable fiber optic sensors, and difficulty in filtering clean, etc., and achieves the effect of small phase detection error, wide application occasions, and reliable operation.

Inactive Publication Date: 2019-01-11
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, on the one hand, the high-frequency component itself will affect the phase detection of the cosine wave (the position of the zero-crossing point changes); The electrical characteristics are equivalent to capacitance, and the voltage at both ends cannot jump, so the falling edge of the sawtooth wave cannot be infinitely short) and the elasticity of the optical fiber itself and many other factors, the frequency is variable, and it is difficult to filter out cleanly; and , when using a filter, in addition to affecting the amplitude-frequency characteristics of the output signal, it will also affect the phase-frequency characteristics of the signal at the same time, that is, the phase of the filter will be affected near the cut-off frequency, which is very important for relying on phase changes. It is very disadvantageous for fiber optic sensors that measure changes in stress

Method used

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Experimental program
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Embodiment 1

[0026] Embodiment 1 Overall structure of the present invention

[0027] like figure 1 Shown, the overall structure of the present invention has, pumping source 1 (the LC962U type pumping source of OCLARO company, central wavelength 980nm, the maximum single-mode output optical power is 750mW) and the first optical coupler 2 (OZ-OPTICS company produces The model is FUSED-12-1060-7 / 125-50 / 50-3U-3mm, the splitting ratio is 10:90 1×2 fiber optic coupler) connected to the input end, 90% output of the first optical coupler 2 The end is connected with the 980nm end of the optical wavelength division multiplexer 3 (COMCORE company 980 / 1060nm single-mode fiber wavelength division multiplexer), and the 1550nm end of the optical wavelength division multiplexer 3 is connected with the delay line adjustable optical fiber 12 (Sichuan Yuxingguang Technology Co., Ltd. Co., Ltd. VDL-40-15-S9-1-FA type motorized optical fiber delay line) is connected to one end, and the other end of the delay...

Embodiment 2

[0029] Embodiment 2 function conversion circuit

[0030] The structure of the function conversion circuit 29 is that one end of the capacitor C3 is connected to the pin 12 of the trigonometric function converter U1 and one end of the resistor R2, and the other end of the capacitor C3 is used as the input end of the function conversion circuit 29, which is recorded as the port ACOS_in , is connected with the output end of the differential amplifier circuit 28; the other end of the resistor R2 is grounded; the pins 2, 3, 4, 5, 8, 11, 13 of the trigonometric function converter U1 are grounded, and the pins 9, 10 are connected to the capacitor C2 One end is connected to -12V power supply, the other end of capacitor C2 is grounded; pin 6 of trigonometric function converter U1 is connected to pin 7, pin 16 is connected to +12V power supply and one end of capacitor C1, and the other end of capacitor C1 is grounded; The pin 1 of the trigonometric function converter U1 is connected to ...

Embodiment 3

[0031] Embodiment 3 Adaptive Amplitude Normalization Circuit

[0032]Because the amplitude of the signal output by the function conversion circuit 29 is relatively small, and is affected by multiple parameters in the optical path and the circuit, the size is indefinite, so the present invention designs an adaptive amplitude normalization circuit 30, which is used to convert the signal output by the function conversion circuit 29 The amplitude is normalized to the optimal size to further improve the accuracy of demodulation. The structure of the adaptive amplitude normalization circuit 30 is that one end of the capacitor C9 is connected to one end of the resistor R3 and the pin 3 of the chip U2, the other end of the resistor R3 is grounded, and the other end of the capacitor C9 is used as an adaptive amplitude normalization The input end of the circuit 30 is recorded as the port ADAPT_in, and is connected with the port ACOS_out of the function conversion circuit 29; the pin 1, ...

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Abstract

A high-precision stress sensor based on Bragg fiber grating provided by the invention belongs to the technical field of optical fiber sensors. The sensor comprises the main structures of a pump source(1), a first photocoupler (2), an optical wavelength division multiplexer (3), and the like. The high-precision stress sensor provided by the invention uses a sinusoidal signal as the modulation signal without generating high-frequency interference, and has the characteristics such as more reliable work, high sensing precision and wide application range.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensors, in particular to a high-precision stress sensor based on Bragg fiber gratings. Background technique [0002] Fiber Bragg grating (FBG) is widely used in the field of sensing technology due to its advantages of anti-electromagnetic interference, chemical resistance, small transmission loss, small size and light weight, and easy mass production. At present, stress sensors are widely used in the field of engineering technology. Especially in emerging fields such as nanoparticle interaction and cell mechanics, there is an urgent need for micro-stress sensors, and the safety monitoring of bridges, tunnels, and building structures is inseparable from micro-stress sensors. Due to the above-mentioned advantages of the fiber Bragg grating, the stress sensor formed by it has higher reliability than other sensors, and is more suitable for use under harsh conditions. [0003] The closest exis...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01L1/24
CPCG01L1/246
Inventor 吴戈林旻
Owner JILIN UNIV
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