Distributed optical fibre acoustic sensors – future applications in audio and acoustics engineering
Distributed optical fibre acoustic sensors – future applications in audio and acoustics engineering
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发表时间：
2016-10
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通讯作者：
P. Golacki;A. Masoudi;K. Holland;T. Newson
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作者：
P. Golacki;A. Masoudi;K. Holland;T. Newson
Bucaro 等人 1 和 Cole 等人 2 于 20 世纪 70 年代首次成功进行了光纤声学传感器实验。这些和后来的发展主要涉及点传感器，其相当于单个麦克风或具有固定数量麦克风的麦克风阵列。光纤声传感器利用压力引起的光纤折射率变化及其由弯曲波引起的几何变形来测量声扰动3。单点光纤声学传感器通常比麦克风更昂贵。然而，如果需要大量传感器，分布式光纤传感器可以提供麦克风阵列的经济高效的替代方案，因为可以将声压级映射为距离的函数。历史上，分布式光纤传感器 (DOFS) 最古老的应用是测量长电信光链路上光纤的完整性。最近，焦点已转向声音和振动的分布式测量4。本文简要回顾了光纤分布式声学传感器技术。首先，我们更详细地研究分布式传感原理并比较不同的方法。在下一节中，我们将讨论 Masoudi 等人设计和构建的系统中使用的相位光时域反射计 (phi-OTDR) 和瑞利反向散射的原理。5。我们将从声学角度讨论该系统的局限性。然后，我们提出了这种系统在声学测量中的可能应用。第 4-6 节介绍并讨论了在混响室中进行的初步实验的结果。
First successful experiments with optical fibre acoustic sensors were performed in 1970s by Bucaro et al.1 and Cole et al.2. Those and later developments were primarily concerned with point sensors which are equivalent to single microphone or a microphone array with fixed number of microphone. Optical fibre acoustic sensors utilise pressure induced variations in the refractive index of the fibre and its geometrical deformation caused by flexural wave to measure acoustic disturbance3. Single point optical fibre acoustic sensors are usually more expensive than microphones. However, if a large number of sensors is needed, distributed optical fibre sensors can offer a cost-effective alternative to microphone array due to the possibility of mapping the sound pressure level as a function of distance. Historically the oldest application of distributed optical fibre sensors (DOFS) were to measure the integrity of optical fibres along long telecom optical links. Just recently the focus has shifted towards distributed measurements of sound and vibration4. This paper briefly reviews the optical fibre distributed acoustic sensor technology. First, we look into distributed sensing principles in more details and compare different methods. In the next section,we will discuss the principle of Phase Optical Time Domain Reflectometry (phi-OTDR) and Rayleigh backscattering, which is used in the system designed and built by Masoudi et al.5. We will discuss the limitations of the system from acoustics point of view. Then, we propose possible applications of such a system in acoustic measurements. In sections 4–6, the results of the preliminary experiment performed in a reverberation chamber are presented and discussed.