Distributed measurement of forward stimulated Brillouin scattering (FSBS) attracted substantial attention for its ability to probe media surrounding optical fibers. Currently, all techniques extract the information from the FSBS-induced local energy transfer among distinct optical tones, this transfer being fundamentally sensitive to intensity perturbations imposed by nonlinear effects. Instead, here we propose to extract the local FSBS information by measuring the frequency shift of a short optical pulse subject to the phase chirp modulation caused by harmonic FSBS oscillation. In full contrast with existing techniques, the optical pulse is much shorter than the period of the acoustic oscillation, enabling ultrashort spatial resolutions, and its frequency shift is precisely probed by a standard Brillouin optical time-domain analyzer. The proposed technique is validated in both remote and integrally distributed sensing configurations, demonstrating spatial resolutions of 0.8 m and 2 m, respectively, substantially outperforming state-of-the-art techniques.

中文翻译：

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基于Serrodyne分析的分布式光机光纤传感

前向受激布里渊散射（FSBS）的分布式测量因其探测光纤周围介质的能力而引起了人们的广泛关注。当前，所有技术都从FSBS引起的不同光学音调之间的局部能量转移中提取信息，这种转移从根本上对非线性效应引起的强度扰动敏感。取而代之的是，这里我们建议通过测量受到谐波FSBS振荡引起的相位线性调频的短光脉冲的频移来提取本地FSBS信息。与现有技术形成鲜明对比的是，光脉冲比声学振荡的周期短得多，从而可以实现超短的空间分辨率，并且其频移可以通过标准的布里渊（Brillouin）光学时域分析仪精确探测到。