A Multipoint Temperature Sensing System Composed of Bragg Gratings

A Bragg grating, multi-point temperature technology, used in thermometers, thermometers, instruments and other directions with physical/chemical changes, can solve the problems of variable frequency, difficult to filter clean, unfavorable optical fiber sensors, etc., to achieve reliable work.

Inactive Publication Date: 2020-05-22
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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  • A Multipoint Temperature Sensing System Composed of Bragg Gratings
  • A Multipoint Temperature Sensing System Composed of Bragg Gratings
  • A Multipoint Temperature Sensing System Composed of Bragg Gratings

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Experimental program
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Embodiment 1

[0027] Embodiment 1 Overall structure of the present invention

[0028] Such as figure 1 As shown, the overall structure of the present invention has, pumping source 1 (VENUS series 980nm high-power single-mode pumping light source of Shanghai Knet Laser Technology Co., Ltd., the model is VLSS-980-B, and the maximum single-mode output optical power is 1200mW) is connected to the 980nm end of the optical wavelength division multiplexer 2 (the fusion tapered 980 / 1550nm pump optical wavelength division multiplexing coupler produced by Shanghai Hanyu Optical Fiber Communication Technology Co., Ltd.), and the 1550nm end of the optical wavelength division multiplexer 2 Connect with one end of the optical fiber wound on the first piezoelectric ceramic 11 (cylindrical piezoelectric ceramic, outer diameter 50mm, inner diameter 40mm, height 50mm), the other end of the optical fiber wound on the first piezoelectric ceramic 11 is connected with the first The input end of the optical iso...

Embodiment 2

[0030] Embodiment 2 function conversion circuit

[0031]The structure of the function conversion circuit 27 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 terminal of the function conversion circuit 27, which is recorded as the port ACOS_in , is connected with the output end of the second photoelectric conversion circuit 26; 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 One end of C2 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 Grounding; pin 1 of the trigonometric function converter U1 is con...

Embodiment 3

[0032] Embodiment 3 Adaptive Amplitude Normalization Circuit

[0033] Because the signal amplitude of the function conversion circuit 27 output is relatively small, and is affected by multiple parameters in the optical path and the circuit, the size is indefinite, so the present invention has designed an adaptive amplitude normalization circuit 28, which is used for the signal output by the function conversion circuit 27 The amplitude is normalized to the optimal size to further improve the accuracy of demodulation. The specific structure 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 input end of the adaptive amplitude normalization circuit 28, which is recorded as the port ADAPT_in , is connected with the port ACOS_out of the function transformation circuit 27; the pin 1, the pin 7, the pin 8, and the pin 14 of t...

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Abstract

The invention relates to a multi-point temperature sensing system composed of Bragg gratings, which belongs to the technical field of optical fiber sensors. Its main structures include a pump source (1), an optical wavelength division multiplexer (2), an erbium-doped optical fiber (3) and the like. The invention uses a sinusoidal signal as a modulation signal, does not generate high-frequency interference, and has the characteristics of more reliable operation, high sensing precision, wide application range and the like.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensors, in particular to a multi-point temperature sensing system composed of Bragg 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, temperature sensors play an important role in safe production, especially in high-risk places such as mines, where temperature monitoring is crucial. However, most of the traditional temperature sensors are realized by the change of electrical signal, and the temperature sensor based on the change of electrical signal is greatly limited in practical application. Additional safety hazards, on the other hand, when used in harsh environments, they are greatly disturbed by the environment and the transmission is inconvenient. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01K11/32G01K11/3206
CPCG01K11/32
Inventor 吴戈张栋
Owner JILIN UNIV
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