High-resolution Brillouin optical correlation domain analysis with no spectral scanning.
High-resolution Brillouin optical correlation domain analysis with no spectral scanning.
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DOI：
10.1364/oe.24.027253
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发表时间：
2016-11
期刊：
影响因子：
3.8
通讯作者：
Eyal Preter;D. Ba;Y. London;Orel Shlomi;Y. Antman;A. Zadok
中科院分区：
文献类型：
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作者：
Eyal Preter;D. Ba;Y. London;Orel Shlomi;Y. Antman;A. Zadok
分布式布里渊光纤传感器通常依赖于通过对泵浦和信号波之间的频率偏移进行频谱扫描来重建稳态布里渊增益谱(BGS)。在这项工作中，我们提出并演示了另一种方法，即从放大信号波的阶跃响应的时间瞬时分析中提取局部布里渊频移(BFS)。测量仅在泵浦和信号之间的两个任意频率偏移处进行。不需要光谱扫描，也不需要参考BGS的先验知识。受激布里渊散射微分方程组的解析解和数值解支持这一原理。测量了一根2米长光纤的BFS，测量精度为1 MHz，动态范围为200 MHz。在布里渊光学相关域分析(B-OCDA)实验中也进行了瞬时测量，分辨率为4 cm，标准偏差为2.4 MHz，动态范围为100 MHz。在测量中正确地识别出了一个4厘米宽的热点。可以在泵浦脉冲的单次飞行中寻址多个相关峰。这是第一个没有光谱扫描的B-OCDA。这一新的测量概念可能适用于随机存取、分布式和动态的声音和振动监测。
Distributed Brillouin fiber sensors typically rely on the reconstruction of the steady-state Brillouin gain spectrum (BGS), through spectral scanning of the frequency offset between the pump and signal waves. In this work, we propose and demonstrate an alternative approach, in which the local Brillouin frequency shift (BFS) is extracted from temporal transient analysis of the step response of the amplified signal wave. Measurements are taken at only two arbitrary frequency offsets between pump and signal. No spectral scanning and no prior knowledge of a reference BGS are necessary. The principle is supported by analytic and numeric solutions of the differential equations of stimulated Brillouin scattering. The BFS of a 2 meters-long fiber under test was measured with 1 MHz accuracy and a dynamic range of 200 MHz. Transient measurements were also performed in a Brillouin optical correlation domain analysis (B-OCDA) experiment with 4 cm resolution, standard deviation of 2.4 MHz and 100 MHz dynamic range. A 4 cm-wide hot-spot was properly identified in the measurements. Multiple correlation peaks could be addressed in a single flight of a pump pulse. The results represent the first B-OCDA that is free of spectral scanning. This new measurement concept may be applicable to random-access distributed and dynamic monitoring of sound and vibration.