Multi-point dynamic strain sensing using external modulation-based Brillouin optical correlation domain analysis

We report a novel technique to detect dynamic strain variations simultaneously at multiple locations. Our technique is based on Brillouin optical correlation domain analysis implemented through external modulation to generate multiple independently-accessible correlation peaks within the sensing fiber. Experiments are carried out to demonstrate the precise determination of Brillouin frequency shift (BFS) from multiple locations independently. As a proof of principle, two correlation peaks are generated within a 1 km long fiber and their independent tunability is verified experimentally by mapping the spatial profile of the two correlations. We also experimentally demonstrate the detection of dynamic strain variations at two locations simultaneously, each with a spatial resolution of 60 cm over 100 m long fiber. (c) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement