Spontaneous Brillouin scattered light time-domain reflectometer on basis of double laser frequency locking

An optical time domain reflectometer and Brillouin scattering technology, which is applied in the field of optical fiber sensor networks, can solve the problems of decreasing measurement accuracy, affecting the consistency of optical fiber temperature and stress measurement accuracy measurement, etc. The effect of simplifying the coherent demodulation method and eliminating the system measurement error

Inactive Publication Date: 2011-07-20
CHINA JILIANG UNIV
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Problems solved by technology

The Brillouin frequency shift obtained by coherent demodulation is directly related to this wavelength difference, so the instability of the wavelength difference will affect the accuracy and consistency of the fiber temperature and stress measurement, and the wide linewidth will make the measurement accuracy worse. decline

Method used

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  • Spontaneous Brillouin scattered light time-domain reflectometer on basis of double laser frequency locking
  • Spontaneous Brillouin scattered light time-domain reflectometer on basis of double laser frequency locking
  • Spontaneous Brillouin scattered light time-domain reflectometer on basis of double laser frequency locking

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Embodiment Construction

[0021] figure 1 As shown, the Spontaneous Burrillouin Scattered Light Time Domain Reflectometer based on dual-laser frequency-locking of the present invention includes two semiconductor lasers, respectively laser 1 as incident light and laser 2 as local oscillator light, and their wavelength difference Set to approach the spontaneous Brillouin scattering frequency shift of the sensing fiber 10 (typical value: 10.8 GHz). Most of the light from the laser 1 is used as the sensing laser, and its emitted light is output to the detection optical path through the coupler 4. First, it is modulated into pulsed light by the electro-optic modulator 6 controlled by the pulse generator 7, then it is further amplified by the fiber amplifier 8, and finally passed through The fiber optic circulator 9 enters the sensing fiber 10 . When the modulated pulsed light enters the optical fiber, it is continuously scattered in the optical fiber to obtain Brillouin scattered light. The Brillouin scat...

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Abstract

The invention discloses a spontaneous Brillouin scattered light time-domain reflectometer on the basis of double laser frequency locking, which is mainly applied to the technical field of optical fiber sensing nets. The invention aims at providing a spontaneous Brillouin scattered light time-domain reflectometer with small volume, low price and stable wavelength difference between vibration light and incident light on the basis of the double-laser frequency locking. In order to solve the problems, the invention adopts the technical scheme that the spontaneous Brillouin scattered light time-domain reflectometer comprises a laser used as the incident light and a laser used as the vibration light. Light emitted by the laser used as the incident light is output to a detecting light path. After the light emitted from the detecting light path passes through an electro-optical modulator, a light amplifier and a circulator controlled by a pulser, the light enters into a sensing fiber to obtain Brillouin scattered light. The Brillouin scattered light passing the circulator and the light emitted by the laser used as the vibration light are in beat frequency interfere through a coupler. At last, electrical signals are output by a photoelectric detector and are collected and processed by a computer with a data acquisition card.

Description

technical field [0001] The invention relates to a self-Brillouin scattered light time-domain reflectometer based on double-laser frequency-locking, which is mainly used in the technical field of optical fiber sensor networks. Background technique [0002] In the current field of distributed optical fiber sensing, sensors based on the principle of optical fiber Brillouin scattering occupy an important position, and according to the specific application technology categories, they are divided into sensors based on spontaneous Brillouin and stimulated Brillouin scattering. The basic technical principle involved in the invention is derived from the spontaneous Burrillouin scattering in the optical fiber. Part of the photons of the incident light are scattered by the thermoacoustic phonons in the fiber, and the wavelength of the photons is slightly shifted to become Brillouin scattered photons, and the wavelength shift is related to the temperature and stress of the fiber. This ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01D3/028
Inventor 李裔张在宣金尚忠
Owner CHINA JILIANG UNIV
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