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Optical Engineering • Open Access

Enhanced performance for differential detection in coherent Brillouin optical time-domain analysis sensors
Author(s): Liyang Shao; Yunpeng Zhang; Zonglei Li; Zhiyong Zhang; Xihua Zou; Bin Luo; Wei Pan; Lianshan Yan

Paper 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.

Paper Details

Date Published: 4 November 2016
PDF: 5 pages
Opt. Eng. 55(11) 117101 doi: 10.1117/1.OE.55.11.117101
Published in: Optical Engineering Volume 55, Issue 11
Show Author Affiliations
Liyang Shao, Southwest Jiaotong Univ. (China)
Yunpeng Zhang, Southwest Jiaotong Univ. (China)
Zonglei Li, Southwest Jiaotong Univ. (China)
Zhiyong Zhang, Southwest Jiaotong Univ. (China)
Xihua Zou, Southwest Jiaotong Univ. (China)
Bin Luo, Southwest Jiaotong Univ. (China)
Wei Pan, Southwest Jiaotong Univ. (China)
Lianshan Yan, Southwest Jiaotong Univ. (China)

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