Fiber sensor based on Michelson interference

An optical fiber sensor and optical coupler technology, which is applied in the direction of using optical devices to transmit sensing components, can solve the problems of variable frequency, difficult to filter clean, unfavorable optical fiber sensors, etc., and achieves the effect of reliable operation.

Inactive Publication Date: 2018-12-18
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 disadvantageous for fiber optic sensors that measure changes in stress

Method used

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  • Fiber sensor based on Michelson interference
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  • Fiber sensor based on Michelson interference

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Experimental program
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Effect test

Embodiment 1

[0028] Embodiment 1 Overall structure of the present invention

[0029] 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 The output end of 1200mW) is connected to the input end of the first optocoupler 2 (produced by OZ-OPTICS company, model is FUSED-12-1064-7 / 125-90 / 10-3U-3mm, splitting ratio is 90:10) , one output end of the first optical coupler is connected with the 980nm end of the optical wavelength division multiplexer 3 (the fusion tapered 980 / 1550nm pump optical wavelength division multiplexing coupler produced by Shanghai Hanyu Optical Fiber Communication Technology Co., Ltd.), and the optical wave The 1550nm end of the demultiplexer 3 is connected to one end of an optical fiber wound on the first piezoelectric ceramic 12 (cylindrical p...

Embodiment 2

[0031] Embodiment 2 function transformation circuit

[0032]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 terminal of the function conversion circuit 29, which is denoted as the port ACOS_in , is connected with the output end of the second photoelectric conversion 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 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 ...

Embodiment 3

[0033] Embodiment 3 Adaptive Amplitude Normalization Circuit

[0034] 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 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 30, which is recorded as the port ADAPT_in , is connected with the port ACOS_out of the function conversion circuit 29; the pin 1, the pin 7, the pin 8 and the pin 14 ...

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Abstract

The invention discloses a fiber sensor based on Michelson interference and belongs to the technical field of the fiber sensor. A main structure of the fiber sensor comprises a pump source (1), a firstoptical coupler (2), an optical wavelength division multiplexer (3) and the like. According to the fiber sensor, a sinusoidal signal is taken as a modulation signal and high frequency interference isnot generated. The fiber sensor is characterized by relatively reliable working, 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 an optical fiber sensor based on Michelson interference. 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 Bragg fiber grating sensors wi...

Claims

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Application Information

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IPC IPC(8): G01D5/353
CPCG01D5/353
Inventor 吴戈邱天
Owner JILIN UNIV
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