Influence of laser linewidth on performance of Brillouin optical time domain reflectometry

The effects of optical sources with different laser linewidths on Brillouin optical time domain reflectometry （BOTDR） are investigated numerically and experimentally. Simulation results show that the spectral linewidth of spontaneous Brillouin scattering remains almost constant when the laser linewi...

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Bibliographic Details
Published inChinese physics B Vol. 22; no. 7; pp. 257 - 261
Main Author 郝蕴琦 叶青 潘政清 蔡海文 瞿荣辉
Format Journal Article
LanguageEnglish
Published 01.07.2013
Subjects
Brillouin zone
Computer simulation
Constants
Detection
DFB激光器
Fibers
Lasers
Mathematical models
Reflectometry
Time domain
传感光纤
光纤激光器
反射性能
布里渊光时域反射计
数值模拟
比较实验
激光线宽
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ISSN1674-1056
2058-3834
1741-4199
DOI10.1088/1674-1056/22/7/074214

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Summary:The effects of optical sources with different laser linewidths on Brillouin optical time domain reflectometry （BOTDR） are investigated numerically and experimentally. Simulation results show that the spectral linewidth of spontaneous Brillouin scattering remains almost constant when the laser linewidth is less than 1 MHz at the same pulse width; otherwise, it increases sharply. A comparison between a fiber laser （FL） with 4-kHz linewidth at 3 dB and a distributed feedback （DFB） laser with 3-MHz linewidth is made experimentally. When a constant laser power is launched into the sensing fiber, the fitting linewidths of the beat signals （backscattered Brillouin light and local oscillator （LO）） is about 5 MHz wider for the DFB laser than for the FL and the intensity of the beat signal is about a half. Furthermore, the frequency fluctuation in the long sensing fiber is lower for the FL source, yielding about 2 MHz less than that of the DFB laser, indicating higher temperature/strain resolution. The experimental results are in good agreement with the numerical simulations.
Bibliography:Hao Yun-Qi, Ye Qing, Pan Zheng-Qing, Cai Hai-Wen, and Qu Rong-Hui a） Shanghai Key Laboratory of All Solid-state Laser and Applied Techniques, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China b） Department of Technology Physics, Zhengzhou University of Light Industry, Zhengzhou 450002, China
Brillouin optical time domain reflectometry （BOTDR）;laser linewidth;distributed feedback laser;fiber laser
The effects of optical sources with different laser linewidths on Brillouin optical time domain reflectometry （BOTDR） are investigated numerically and experimentally. Simulation results show that the spectral linewidth of spontaneous Brillouin scattering remains almost constant when the laser linewidth is less than 1 MHz at the same pulse width; otherwise, it increases sharply. A comparison between a fiber laser （FL） with 4-kHz linewidth at 3 dB and a distributed feedback （DFB） laser with 3-MHz linewidth is made experimentally. When a constant laser power is launched into the sensing fiber, the fitting linewidths of the beat signals （backscattered Brillouin light and local oscillator （LO）） is about 5 MHz wider for the DFB laser than for the FL and the intensity of the beat signal is about a half. Furthermore, the frequency fluctuation in the long sensing fiber is lower for the FL source, yielding about 2 MHz less than that of the DFB laser, indicating higher temperature/strain resolution. The experimental results are in good agreement with the numerical simulations.
11-5639/O4
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SourceType-Scholarly Journals-1
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content type line 23
ISSN:1674-1056
2058-3834
1741-4199
DOI:10.1088/1674-1056/22/7/074214