A high-precision optical fiber sensor based on Mach-Zehnder interference structure

A technology of optical fiber sensor and interference structure, which is applied in the direction of using optical devices to transmit sensing components, etc., can solve the problems of variable frequency, difficult to filter out, and influence of signal phase-frequency characteristics, etc., to achieve small phase detection error and application Wide range of occasions and reliable results

Inactive Publication Date: 2019-09-13
JILIN UNIV
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  • 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 unfavorable for fiber optic sensors that measure changes in physical quantities such as stress or temperature

Method used

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  • A high-precision optical fiber sensor based on Mach-Zehnder interference structure
  • A high-precision optical fiber sensor based on Mach-Zehnder interference structure
  • A high-precision optical fiber sensor based on Mach-Zehnder interference structure

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Embodiment 1

[0026] Embodiment 1 Overall structure of the present invention

[0027] Such as 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-12-1064-7 / 125-90 / 10-3U-3mm, the splitting ratio is 90:10) the input end is connected, the 90% output end of the first optical coupler 2 is connected with the optical wavelength division multiplexer 3 (COMCORE company 980 / 1060nm single-mode optical fiber wavelength division multiplexer) is connected to the 980nm end, and the 1550nm end of the optical wavelength division multiplexer 3 is wound on the first piezoelectric ceramic 12 (cylindrical piezoelectric ceramic, outer diameter 50mm, One end of the optical fiber on the inner diameter 40mm, high 50mm) is connected, and the other end of the optical fiber w...

Embodiment 2

[0029] Embodiment 2 function conversion circuit

[0030] The structure of the function conversion circuit 28 is as follows: 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 28, which is recorded as the port ACOS_in , is connected with the output end of the second photoelectric conversion circuit 27; 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 U...

Embodiment 3

[0031] Embodiment 3 Adaptive Amplitude Normalization Circuit

[0032] Because the amplitude of the signal output by the function conversion circuit 28 is 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 29, which is used to convert the signal output by the function conversion circuit 28 The amplitude is normalized to the optimal size to further improve the accuracy of demodulation. The structure of the adaptive amplitude normalization circuit 29 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 29 is recorded as the port ADAPT_in, and is connected with the port ACOS_out of the function conversion circuit 28; the pin 1, the pin 7,...

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Abstract

The invention relates to a high-precision optical fiber sensor based on a Mach-Zehnder interference structure and belongs to the technical field of optical fiber sensors. The high-precision optical fiber sensor mainly comprises a pumping source (1), a first optical coupler (2), an optical wavelength division multiplexer (3) and the like. The high-precision optical fiber sensor provided by the invention uses a sinusoidal signal as a modulating signal, can not produce high-frequency interference and has the characteristics of 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 optical fiber sensor based on a Mach-Zehnder interference structure. 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. Especially in micro-stress detection, temperature detection in harsh environments, etc., fiber optic sensors have unique advantages. On the one hand, very small changes in temperature or stress can be detected sensitively by fiber Bragg gratings, with high sensitivity. On the one hand, in harsh environments such as humidity and strong electromagnetic interference, the fiber Bragg grating is not easy to damage, the working performance is not affected, and the signal transmission is not disturbed. These advantages make B...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01D5/353
Inventor 吴戈邱天
Owner JILIN UNIV
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