Brillouin optical time domain analysis (BOTDA) temperature and strain simultaneous measurement method based on large effective area fiber (LEAF)

A measurement method and optical fiber technology, applied in the field of optoelectronics, to achieve the effect of improving the dynamic range and resolution, overcoming the constraints of measurement results, and having broad application prospects

Active Publication Date: 2013-04-24
UNIV OF ELECTRONIC SCI & TECH OF CHINA
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Problems solved by technology

However, the noise of the optical power detector itself and the measurement value fluctuation caused by factors such as measurement accuracy are still the main factors restricting the measurement accuracy of temperature and strain, as well as the resolution and dynamic range of the sensing system

Method used

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  • Brillouin optical time domain analysis (BOTDA) temperature and strain simultaneous measurement method based on large effective area fiber (LEAF)
  • Brillouin optical time domain analysis (BOTDA) temperature and strain simultaneous measurement method based on large effective area fiber (LEAF)
  • Brillouin optical time domain analysis (BOTDA) temperature and strain simultaneous measurement method based on large effective area fiber (LEAF)

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Embodiment

[0028] The wavelength continuous light source with a wavelength range of 400nm-2400nm passes through the optical attenuator 2 to obtain probe light with appropriate intensity, and its spectrum is as follows figure 1 shown, and record its center frequency as . A narrow linewidth light source with a frequency of about 1 MHz is divided into two by a 1:2 coupler 10 . After the first optical signal passes through the polarization controller 8, it is modulated by the electro-optical intensity modulator 7, and the parameters are set so that the output frequency of the modulator 7 is , a pulsed light with a pulse width of 10ns, where is the Brillouin frequency shift. After filtering the pulse signal with an optical filter, only the output frequency is pulse. Then the pulse signal enters the polarization scrambler 6, so that the polarization state of the pulse signal is continuously changed, thereby avoiding the polarization mismatch between the pump pulse optical signal and t...

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Abstract

The invention discloses a Brillouin optical time domain analysis (BOTDA) temperature and strain simultaneous measurement method based on large effective area fiber (LEAF). Aimed at the defect that absolute power of an optical signal can not be measured accurately so that measurement accuracy can not be improved in an existing temperature and strain simultaneous measurement method, the simultaneous measurement of temperature and strain is put forward by making use of the feature that a simulated Brillouin gain spectrum in the LEAF has a plurality of gain peaks. Due to the fact that continuous detecting light and narrow-line broad-pulse pump light produce stimulated Brillouin scattering in the LEAF, by measuring the Brillouin frequency shift and the line width of a first gain peak and a second gain peak of a Brillouin scattering signal and fitting the measured data with a fitting algorithm, measurement along fiber temperature and strain distribution is completed. According to the BOTDA temperature and strain simultaneous measurement method based on the LEAF, the absolute power of the Brillouin scattering signal does not need to be measured, dynamic property and spatial resolution of a BOTDA system are improved effectively, so that the BOTDA temperature and strain simultaneous measurement method based on the LEAF has an extensive application prospect in a distributed optical fiber sensing system.

Description

technical field [0001] The invention belongs to the field of optoelectronic technology, relates to optical fiber sensing technology, in particular to a BOTDA temperature and strain simultaneous measurement method based on LEAF optical fiber. Background technique [0002] In distributed Brillouin sensing, there are two types of Brillouin optical time domain reflectometer BOTDR and Brillouin optical time domain reflectometry BOTDA. In conventional temperature and strain sensing systems, both BOTDR and BOTDA use single-mode fiber as the sensing medium, and by analyzing the Brillouin scattering gain spectrum, that is, the power of the Brillouin signal and the Brillouin frequency shift (pump The difference between the central frequency of the Pu light pulse and the central frequency of the Brillouin scattering) changes to obtain information on temperature and strain. [0003] In a distributed Brillouin sensing system, sensing signals at different locations have different transmi...

Claims

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Application Information

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IPC IPC(8): G01K11/32G01B11/16G01K11/322
Inventor 刘永袁飞杨帆洪向前唐琳峰张尚剑
Owner UNIV OF ELECTRONIC SCI & TECH OF CHINA
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