Zhu W, Li M, Lu H, Wen X, Deng S, Jiang C
Opt Express. 2019 Jan 21;27(2):816-826. doi: 10.1364/OE.27.000816.
Gain-profile tracing (GPT) is a useful strategy of distributed sensing in BOTDA technique for achieving high spatial resolution, which has not been used for the dynamic strain measurement previously. In this paper, we propose a modified gain-profile tracing (MGPT) technique for fast dynamic strain measurement while maintaining the advantage of high spatial resolution. This technique is based on a modified pump pulse modulation scheme and the slope-assisted demodulation method. The time consumption using MGPT technique for a single pump pulse measurement of dynamic strain is less by 25% than the conventional GPT technique. The spatial resolution of our BOTDA system using MGPT technique is 50cm and maximal frequency of dynamic strain detection could be up to 53.5 Hz for 248m sensing length. In the experiments, we measure two vibration events spacing 50 cm with the frequency of 14.0 Hz and 17.0 Hz in a 248 m single-mode fiber. The proposed method is a potential real-time dynamic alternative for distributed structural health monitoring.
增益分布追踪（GPT）是布里渊光时域分析（BOTDA）技术中用于实现高空间分辨率的一种有用的分布式传感策略，此前尚未用于动态应变测量。在本文中，我们提出了一种改进的增益分布追踪（MGPT）技术，用于快速动态应变测量，同时保持高空间分辨率的优势。该技术基于一种改进的泵浦脉冲调制方案和斜率辅助解调方法。使用MGPT技术进行单次泵浦脉冲动态应变测量的时间消耗比传统GPT技术少25%。我们使用MGPT技术的BOTDA系统的空间分辨率为50厘米，对于248米的传感长度，动态应变检测的最大频率可达53.5赫兹。在实验中，我们在一根248米的单模光纤中测量了两个间距为50厘米、频率分别为14.0赫兹和17.0赫兹的振动事件。所提出的方法是分布式结构健康监测的一种潜在实时动态替代方案。
