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Wavelength demodulation method for optical fiber sensing

A wavelength demodulation and optical fiber sensing technology, applied in the field of sensing applications, can solve the problems of expensive, bulky and bulky spectrum analyzers, and achieve the effects of high measurement accuracy and strong anti-interference ability.

Inactive Publication Date: 2009-09-16
BEIJING UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method seems to be very simple, but the spectrum analyzer 9 is very expensive, bulky and heavy, and cannot be applied in actual engineering

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  • Wavelength demodulation method for optical fiber sensing
  • Wavelength demodulation method for optical fiber sensing
  • Wavelength demodulation method for optical fiber sensing

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Embodiment Construction

[0028] Preferred embodiments of the present invention will be specifically described below in conjunction with the accompanying drawings.

[0029] According to the wavelength demodulation device of the optical fiber sensor designed according to the method proposed by the present invention, see figure 2, is the experimental structure diagram for FBG sensing wavelength demodulation. It includes an optical coupler 2" that divides the optical signal of wavelength change into two beams of light with equal light intensity, two similar fiber optic loop mirrors connected in parallel, PIN photodiode, signal processing circuit 14, single-chip microcomputer 5 and display 21. The loop mirror Comprise optical coupler, common optical fiber, birefringent optical fiber.The first optical fiber loop mirror is made up of the loop that the first optical coupler 2 and the first optical fiber 11, long birefringent optical fiber 10, the first polarization controller 12 form.The second The optical ...

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Abstract

A wavelength demodulating method of optical sensor is provided, which belongs to the wavelength demodulating technology in optical sensor. The invention utilizes the counting method to the output signal of fiber loop mirror to conduct wavelength demodulating and uses the monotony character of the output light intensity changing with the wavelength of short and birefraction fiber loop mirror to fix the direction of long birefraction optical fiber counting. The counting can be finished by a signal processing circuit which is composed of an amplifier and a comparator and a singlechip. The invention completely avoids measuring the change of wavelength through measuring the width of signal, which has the advantages of strong anti-interference ability and high measuring accuracy.

Description

technical field [0001] The invention is applied in optical fiber sensing, especially fiber Bragg grating (FBG) sensing, where the change of the measured light wavelength is used to determine the change of the sensed quantity (such as temperature, strain, etc.). It belongs to the wavelength demodulation technology in optical fiber sensing. Background technique [0002] In fiber optic sensing, there are some sensors that reflect changes in the sensed quantity through changes in the wavelength of light, typically FBG. When the external sensed quantity, such as temperature or strain, changes, the wavelength of light reflected by the FBG also changes accordingly, and there is a certain functional relationship between the two. If the change of the reflected light wavelength is measured, the change of the physical quantity to be sensed is also measured. This process is called wavelength demodulation. [0003] The existing relatively mature and commercially available wavelength de...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01D5/353G02B6/26G02B6/42G02F1/00
Inventor 何士雅胡曙阳赵啟大
Owner BEIJING UNIV OF TECH