We demonstrate the enlargement of sensing range of Brillouin optical correlation domain analysis (BOCDA) system by introducing the first-order distributed Raman amplification. The time-domain data processing is adopted for the BOCDA system utilizing a gated Brillouin pump, and the Raman amplification is applied to compensate for the depletion of Brillouin pump induced by Rayleigh scattering and Brillouin interaction. The Raman pump is injected in the opposite direction to the propagation of Brillouin pump, where the pumping scheme is optimized by simulations. A differential measurement scheme is additionally introduced for improving spatial resolution and dynamic range. In experiments, we measure the strain distribution along a 52.1 km sensing fiber with 7 cm spatial resolution, where the number of resolving points of measurement is more than 744 000.

中文翻译：

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50 公里范围布里渊光相关域分析，采用一阶后向分布式拉曼放大

我们通过引入一阶分布式拉曼放大来证明布里渊光相关域分析（BOCDA）系统的传感范围的扩大。BOCDA系统采用门控布里渊泵浦进行时域数据处理，并采用拉曼放大来补偿瑞利散射和布里渊相互作用引起的布里渊泵浦损耗。拉曼泵的注入方向与布里渊泵的传播方向相反，其中泵送方案通过模拟进行了优化。另外引入了差分测量方案以提高空间分辨率和动态范围。在实验中，我们以 7 cm 的空间分辨率测量了沿 52.1 km 传感光纤的应变分布，