Enhanced performance for differential detection in coherent Brillouin optical time-domain analysis sensors

Liyang Shao; Yunpeng Zhang; Zonglei Li; Zhiyong Zhang; Xihua Zou; Bin Luo; Wei Pan; Lianshan Yan

doi:10.1117/1.OE.55.11.117101

4 November 2016 Enhanced performance for differential detection in coherent Brillouin optical time-domain analysis sensors

Liyang Shao, Yunpeng Zhang, Zonglei Li, Zhiyong Zhang, Xihua Zou, Bin Luo, Wei Pan, Lianshan Yan

Author Affiliations +

Optical Engineering, Vol. 55, Issue 11, 117101 (November 2016). https://doi.org/10.1117/1.OE.55.11.117101

Abstract

Logarithmic detectors (LogDs) have been used in coherent Brillouin optical time-domain analysis (BOTDA) sensors to reduce the effect of phase fluctuation, demodulation complexities, and measurement time. However, because of the inherent properties of LogDs, a DC component at the level of hundreds of millivolts that prohibits high-gain signal amplification (SA) could be generated, resulting in unacceptable data acquisition (DAQ) inaccuracies and decoding errors in the process of prototype integration. By generating a reference light at a level similar to the probe light, differential detection can be applied to remove the DC component automatically using a differential amplifier before the DAQ process. Therefore, high-gain SA can be employed to reduce quantization errors. The signal-to-noise ratio of the weak Brillouin gain signal is improved from ∼11.5 to ∼21.8 dB. A BOTDA prototype is implemented based on the proposed scheme. The experimental results show that the measurement accuracy of the Brillouin frequency shift (BFS) is improved from ±1.9 to ±0.8 MHz at the end of a 40-km sensing fiber.

CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Liyang Shao, Yunpeng Zhang, Zonglei Li, Zhiyong Zhang, Xihua Zou, Bin Luo, Wei Pan, and Lianshan Yan "Enhanced performance for differential detection in coherent Brillouin optical time-domain analysis sensors," Optical Engineering 55(11), 117101 (4 November 2016). https://doi.org/10.1117/1.OE.55.11.117101

Published: 4 November 2016

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