Distinguish measurement of temperature and strain of laid sensing optical fibers based on BOTDR

Lv Anqiang; Li Yongqian; Li Jing; Liu Zheng

In order to solve the problems that the initial value of Brillouin peak power in laid sensing optical fibers is hard to be obtained and the measurement error of temperature and strain is large based on Brillouin frequency shift and peak power, the method of distinguish measurement of temperature and strain is proposed. The Brillouin frequency shift and relative peak power coefficients of temperature and strain, as well as initial Brillouin frequency shift, were obtained by calibration experiment. The coefficients in Brillouin power equation were obtained by heuristic method according to the reference fiber in known temperature and strain. Then the initial Brillouin power distribution along the laid fiber was obtained. The measurement error caused by multiplicative noises in sensing system was conquered by normalization. The spikes in the Brillouin peak power profiles at positions of changed temperature or strain were eliminated by using spectral width change. The simulated optical path of optical fiber composite submarine power cable in engineering field was established. The measurement experiment of temperature and strain was performed. The results indicate that the measurement accuracy are 4.3℃ and 110 at 5.6 km. The distinguish measurement of temperature and strain for laid sensing fiber can be realized. The method can provide theoretical and experimental basis for engineering applications.

1. Department of Electronic and Communication Engineering,North China Electric Power University,Baoding 071003,China;

2. Information and Network Management Center,North China Electric Power University,Baoding 071003,China

Received Date: 2015-02-05

Rev Recd Date: 2015-03-03

Publish Date: 2015-10-25

Key words:

distinguish measurement of temperature and strain /
Brillouin optical time domain reflectometer /
laid sensing optical fiber /
normalization /
initial Brillouin power distribution

Abstract: In order to solve the problems that the initial value of Brillouin peak power in laid sensing optical fibers is hard to be obtained and the measurement error of temperature and strain is large based on Brillouin frequency shift and peak power, the method of distinguish measurement of temperature and strain is proposed. The Brillouin frequency shift and relative peak power coefficients of temperature and strain, as well as initial Brillouin frequency shift, were obtained by calibration experiment. The coefficients in Brillouin power equation were obtained by heuristic method according to the reference fiber in known temperature and strain. Then the initial Brillouin power distribution along the laid fiber was obtained. The measurement error caused by multiplicative noises in sensing system was conquered by normalization. The spikes in the Brillouin peak power profiles at positions of changed temperature or strain were eliminated by using spectral width change. The simulated optical path of optical fiber composite submarine power cable in engineering field was established. The measurement experiment of temperature and strain was performed. The results indicate that the measurement accuracy are 4.3℃ and 110 at 5.6 km. The distinguish measurement of temperature and strain for laid sensing fiber can be realized. The method can provide theoretical and experimental basis for engineering applications.

HTML

Reference (25)

[1]
[2]	Lv Anqiang, Li Yongqian, Li Jing, et al. Strain and temperature monitoring of optical fiber composite submarine power cable based on brillouin optical time domain reflectometer[J]. High Voltage Engineering, 2014, 40(2):533-539.
[3]	Jiang Q, Sui Q. Technological study on distributed fiber sensor monitoring of high voltage power cable in seafloor[C]//United States:IEEE Computer Society, 2009:1154-1157.
[4]
[5]
[6]	Sun Y, Shi B, Chen S, et al. Feasibility study on corrosion monitoring of a concrete column with central rebar using BOTDR[J]. Smart Structures and Systems, 2014, 13(1):41-53.
[7]
[8]	Wait P C, Newson T P. Landau Placzek ratio applied to distributed fibre sensing[J]. Opt Commun, 1996, 122:141-146.
[9]
[10]	Maughan S M, Kee H H, Newson T P. Simultaneous distributed fibre temperature and strain sensor using microwave coherent detection of spontaneous Brillouin backscatter[J]. Measurement Science and Technology, 2001, 12(7):834.
[11]	Alahbabi M N, Cho Y T, Newson T P. Simultaneous distributed measurements of temperature and strain using spontaneous Raman and Brillouin scattering[C]//Proceedings of EWOFS'04, 2004:488-491.
[12]
[13]	Liu X, Bao X. Brillouin spectrum in LEAF and simultaneous temperature and strain measurement[J]. Journal of Lightwave Technology, 2012, 30(8):1053-1059.
[14]
[15]	Dong Y, Chen L, Bao X. High-spatial-resolution time-domain simultaneous strain and temperature sensor using Brillouin scattering and birefringence in a polarization-maintaining fiber[J]. Photonics Technology Letters, IEEE, 2010, 22(18):1364-1366.
[16]
[17]
[18]	Li T, Dong X, Chan C C, et al. Simultaneous strain and temperature measurement based on a photonic crystal fiber modal-interference interacting with a long period fiber grating[J]. Optics Communications, 2012, 285(24):4874-4877.
[19]
[20]	Parker T R, Farhadiroushan M, Handerek V A, et al. Temperature and strain dependence of the power level and frequency of spontaneous Brillouin scattering in optical fibers[J]. Optics Letters, 1997, 22(11):787-789.
[21]
[22]	Sakairi Y, Uchiyama H, Li Z X, et al. System for measuring temperature and strain separately by BOTDR and OTDR[C]//SPIE, 2002, 4920:274-284.
[23]
[24]	Aoyama K, Nakagawa K, Itoh T. Optical time domain Reflectometry in a single-mode fiber[J]. Quantum Electron, 1981, QE-17(6):862-868.
[25]	Zhang Huayong, Zhang Min, Wang Liwei, et al. Output noise analysis of optical fiber interferometric sensors using a 33 coupler[J]. Measurement Science and Technology, 2011:1-9.

Distinguish measurement of temperature and strain of laid sensing optical fibers based on BOTDR

Abstract

References

Proportional views

通讯作者: 陈斌, bchen63@163.com

Article Metrics

Related

Proportional views