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Fiber sensing system based on fiber laser

A fiber optic sensing system and fiber laser technology, applied in lasers, laser components, phonon exciters, etc., can solve the problems of variable frequency, unfavorable fiber optic sensors, and difficulty in filtering cleanly, and achieve small phase detection errors , Wide range of applications, reliable results

Inactive Publication Date: 2019-01-04
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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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  • Fiber sensing system based on fiber laser
  • Fiber sensing system based on fiber laser
  • Fiber sensing system based on fiber laser

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Example 1 Overall structure of the present invention

[0029] Such as figure 1 As shown, the overall structure of the present invention is that the pump source 1 (LC962U pump source of OCLARO company, the center wavelength is 980nm, the maximum single-mode output optical power is 750mW) is connected to the 980nm end of the optical wavelength division multiplexer 2, and the light wave Divider 2 (COMCORE 980 / 1060nm single-mode optical fiber wavelength division multiplexer) 1550nm end and delay line adjustable fiber 11 Sichuan Yuxingxing Optical Technology Co., Ltd. VDL-40-15-S9-1-FA type Electric fiber delay line) is connected to one end, the other end of the delay line adjustable light 11 is connected to the input end of the first optical isolator 10 (1550nm polarization independent optical isolator), and the control end of the delay line adjustable light 11 is connected to the level The output port of the conversion chip 12 (MAX232) is connected, and the level conversion ...

Embodiment 2

[0031] Example 2 Function Conversion Circuit

[0032] Such as figure 2 As shown, the structure of the function conversion circuit 25 used in the present invention 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 25 , Marked as port ACOS_in, connected to the output end of the differential amplifier circuit 24; the other end of the resistor R2 is grounded; the pins 2, 3, 4, 5, 8, 11, and 13 of the trigonometric function converter U1 are grounded, and the pins 9, 10 is connected to one end of capacitor C2 and -12V power supply, and 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, capacitor C1 The other end of the trigonometric function converter U1 is connected to the ...

Embodiment 3

[0033] Embodiment 3 Adaptive amplitude normalization circuit

[0034] Since the amplitude of the signal output by the function conversion circuit 25 is small and is affected by multiple parameters in the optical path and the circuit, the magnitude is uncertain. Therefore, the present invention designs an adaptive amplitude normalization circuit 26 to convert the signal output by the function conversion circuit 25. The amplitude of is normalized to the optimal size to further improve the accuracy of demodulation. The structure of the adaptive amplitude normalization circuit 26 is that one end of the capacitor C11 is connected to one end of the resistor R21 and the pin 3 of the chip U2, the other end of the resistor R21 is grounded, and the other end of the capacitor C11 is used as the adaptive amplitude. The input terminal of circuit 26, marked as port ADAPT_in, is connected to port ACOS_out of function conversion circuit 25; pin 1, pin 7, pin 8, and pin 14 of chip U2 are all grou...

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Abstract

The invention discloses a fiber sensing system based on a fiber laser, and belongs to the technical field of fiber sensors. The main structure of the system comprises a pump source (1), an optical multiplexer (2), and an Er-doped optical fiber (3). According to the invention, a sine signal is taken as a modulation signal, and no high-frequency interference can be generated, so the system is more reliable in working, is high in sensing precision, and is wide in application range.

Description

Technical field [0001] The invention belongs to the technical field of optical fiber sensors, and particularly relates to an optical fiber sensing system based on an optical fiber laser. Background technique [0002] Fiber Bragg grating (FBG) is widely used in the field of sensing technology because of its advantages such as anti-electromagnetic interference, chemical resistance, low transmission loss, small size and light weight, and easy mass production. Especially in micro-stress detection and temperature detection in harsh environments, fiber optic sensors have unique advantages. On the one hand, very small changes in temperature or stress can be detected by Bragg fiber gratings sensitively, with high sensitivity. On the one hand, in harsh environments such as humidity and strong electromagnetic interference conditions, the Bragg fiber grating is not easy to be damaged, the working performance is not affected, and the signal transmission is not disturbed. These advantages ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01K11/32H01S3/067G01K11/3206
CPCH01S3/067G01K11/3206
Inventor 吴戈张栋
Owner JILIN UNIV
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