Demodulating device of multi-channel high-precision fiber grating sensing and demodulating method thereof

A fiber grating, multi-channel technology, applied in the direction of using optical devices to transmit sensing components, can solve the problems of fiber grating failure, increase in reflection amplitude difference, fiber transmission loss fiber grating reflection spectrum amplitude dynamic change, etc. Avoid large power fluctuations, high stability, and improve long-term detection capabilities and detection accuracy

Active Publication Date: 2013-07-10
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, in actual applications, after each fiber grating is installed and wired, the amplitude of the reflection spectrum will change, especially as the measurement environment changes, such as in an ultra-low temperature environment, when the wiring is bent too much, the fixing glue deteriorates and the fiber is coated The deformation of the layer material will lead to unpredictable dynamic changes in the fiber transmission loss and the amplitude of the reflection spectrum of the fiber Bragg grating, which will increase the difference in the reflection amplitude of multiple channels in each channel, and some reflection peaks of the fiber Bragg grating cannot be detected and fail.

Method used

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  • Demodulating device of multi-channel high-precision fiber grating sensing and demodulating method thereof
  • Demodulating device of multi-channel high-precision fiber grating sensing and demodulating method thereof
  • Demodulating device of multi-channel high-precision fiber grating sensing and demodulating method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0082] Such as figure 1 As shown, the multi-channel high-precision fiber grating sensing demodulation device includes a broadband light source 1, a fixed optical attenuator 2, an optical isolator 3, a tunable FP filter 4, an optical amplifier 5, a fiber coupler 6, and a fiber FP standard Tool 7, electronically controlled adjustable optical attenuator 8, 1×N optical switch 9, multiple optical fiber passive components 11, fiber grating sensor array 12, first photodetector 13, second photodetector 16, acquisition card 14 and a computer 15; wherein the fiber coupler 6 uses a fiber coupler with a splitting ratio of 90:10, and the fiber passive component 11 uses a fiber circulator.

[0083] The output end of the broadband light source 1 is connected to the fixed optical attenuator 2 through a single-mode fiber jumper, and the fixed optical attenuator 2 is selected so that the light intensity input to the tunable FP filter 4 meets the limit requirements of its entrance power. The bro...

Embodiment 2

[0088] Such as figure 2 As shown, the multi-channel high-precision fiber grating sensing demodulation device of the present invention includes a broadband light source 1, a fixed optical attenuator 2, an optical isolator 3, a tunable FP filter 4, an optical amplifier 5, a fiber coupler 6, and an optical fiber FP Etalon 7, electronically controlled adjustable optical attenuator 8, 1×N optical fiber beam splitter 10, multiple optical fiber passive components 11, fiber grating sensor array 12, first photodetector 13, multiple second photodetectors 16. Acquisition card 14 and computer 15; the optical fiber coupler 6 adopts the optical fiber coupler with a splitting ratio of 90:10, and the optical fiber passive device 11 adopts the optical fiber circulator.

[0089] The output end of the broadband light source 1 is connected to the fixed optical attenuator 2 through a single-mode fiber jumper, and the fixed optical attenuator 2 is selected so that the light intensity input to the ...

Embodiment 3

[0094] In the multi-channel high-precision fiber grating demodulation method of the present invention, the computer 15 controls the acquisition card 14 to output a 10 Hz sawtooth wave analog signal as the driving voltage of the tunable FP filter 4, and the obtained frequency is 10 Hz, the wavelength resolution is 5 pm, and the wavelength range is 10 Hz. The 40nm broadband scanning laser output is amplified by the optical amplifier 5 to obtain a high-power output scanning laser. Using a 90:10 fiber coupler 6, 10% of the scanning laser is transmitted to the optical fiber FP etalon 7, which will be filtered by the tunable FP The device 7 obtains a one-to-one correspondence between the sampling point of the scanning laser and the wavelength, which plays a role in real-time wavelength correction and ensures high wavelength repeatability of the demodulation system.

[0095] For the multi-channel high-precision fiber grating demodulation process in the above example 1: 90% of the demo...

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Abstract

The invention discloses a demodulating device of multi-channel high-precision fiber grating sensing and a demodulating method of the demodulating device of the multi-channel high-precision fiber grating sensing. According to the demodulating device of the multi-channel high-precision fiber Bragg grating sensing, a broadband light source, a turnable FP filter and a light amplifier are connected in series and form a turnable laser, and high-stability high-power turnable laser output is obtained. Reflected signal amplitude of a fiber bragging grating serves as dynamic feedback, and an electronic control variable optical attenuator is used for dynamically adjusting the optical power decrement corresponding to each fiber grating wavelength in real time. Therefore, a sending signal optical power with the high signal to noise ratio and the stable amplitude is obtained under the condition of each fiber grating wavelength. Unevenness of the light source and array arrangement of fiber grating sensors and unpredictable dynamic changes of the fiber grating sensors in the process of utilization are compensated compressively. Therefore, long-term detection ability and the detection precision of the fiber grating sensors are effectively improved. In addition, the demodulating device of the multi-channel high-precision fiber grating sensing and the demodulating method of the demodulating device of the multi-channel high-precision fiber grating sensing have a good application prospect in the aerospace field, in the aviation field, in the petrifaction field, in the construction field and in the power field.

Description

technical field [0001] The invention belongs to the field of optical fiber grating sensing. The demodulation device and method can be used for demodulation of various strain, temperature, pressure and other sensors based on optical fiber gratings, and the application occasions include aerospace, aviation, petrochemical, civil engineering and electric power. Background technique [0002] Fiber Bragg grating sensing system uses light as the carrier and optical fiber as the medium. In addition to the advantages of small size, light weight, wide bandwidth, high sensitivity, strong anti-electromagnetic interference and strong corrosion resistance, it is also an absolute code for wavelength, not affected by optical power fluctuations, integrating sensing and transmission, and easy to use. Manufactured and embedded in the material, the measurement of stress, strain, temperature and other physical quantities has been realized. Compared with traditional electrical sensing systems, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01D5/26
Inventor 江俊峰刘铁根宋璐瑶刘琨王双尹金德何盼
Owner TIANJIN UNIV
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