Investigation of Brillouin effects in carbon coating single-mode fiber using for inspection of pipeline buckling

Lufan Zou; Xiaoyi Bao; Fabien Ravet; Yun Li; Liang Chen; Mei Du; David DiGiovanni

doi:10.1117/12.630858

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10 November 2005 Investigation of Brillouin effects in carbon coating single-mode fiber using for inspection of pipeline buckling

Lufan Zou, Xiaoyi Bao, Fabien Ravet, Yun Li, Liang Chen, Mei Du, David DiGiovanni

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Proceedings Volume 6004, Fiber Optic Sensor Technology and Applications IV; 600405 (2005) https://doi.org/10.1117/12.630858
Event: Optics East 2005, 2005, Boston, MA, United States

Abstract

A conventional SMF-28 was used to conduct localized pipe-wall buckling monitoring in a section of energy pipe with 2,667 mm (105 in) in length and 762 mm (30 in) in diameter by a coherent probe-pump based distributed Brillouin fiber sensor with 15 cm spatial resolution. The locations of pipe-wall buckling have been found by measuring the strain distributions along the outer surface of the pipe. However the sensing fiber (SMF-28) was broken when the bending load increased above 1335 kN (300 kips), which caused the sensing fiber experienced more than the compressive strains of -8,084 με. In order to get strain data after pipeline buckling happens, a high strength sensing fiber with carbon coating instead of conventional acrylate coating should be used. The Brillouin measurement on the carbon coating single-mode fiber has Brillouin frequency shift of v_B 12.479 GHz at wavelength of 1320 nm and room temperature. The measured Brillouin bandwidth Δv_B is equal to 66 MHz. The central Brillouin frequency shows a strong dependence on strain with 1.510 GHz shift at 2.5% elongation. The excellent linearity of the central frequency v_B on strain is confirmed and the strain coefficient was measured as 16.21 με/MHz. Its strain-stress relation keeps linearity up to 2.5% elongation, which is much bigger than that of SMF-28.

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Lufan Zou, Xiaoyi Bao, Fabien Ravet, Yun Li, Liang Chen, Mei Du, and David DiGiovanni "Investigation of Brillouin effects in carbon coating single-mode fiber using for inspection of pipeline buckling", Proc. SPIE 6004, Fiber Optic Sensor Technology and Applications IV, 600405 (10 November 2005); https://doi.org/10.1117/12.630858

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