Aliased noises elevate the ultimate noise level of a pulse-triggered time-division-multiplexing (TDM) interferometric fiber-optic sensor array. Here we for the first time present an analytical model of the aliasing factor based on noise power spectral density analysis of the interferometric fiber sensor array. In contrast to the previous reports, the aliasing factor is found not only dependent on the pulse width and the repetition frequency, but also on the rising time of the pulse when matched filters are applied to suppress the noise components out of the main lobe. The model also indicates the explicit scaling rule between the aliasing factor and the number of TDM channels. The model are experimentally validated by measuring the noise floors under different combinations of pulse parameters. Based on the model, an ultra-low noise floor of -114 dB ref rad/Hz−−−√\sqrt{\mathbf {Hz}} (i.e. 2 μ\boldsymbol{\mu}rad/Hz−−−√\sqrt{\mathbf {Hz}}) is achieved and up to 6 interferometric sensors can be multiplexed, which, to the best of knowledge, represents the lowest noise level to date for the TDM interferometric fiber-optic sensor array. Our results reveal the prominent influence of the pulse rising time on the aliased noises and provides a practical approach to suppress noise floor of TDM sensor array.

中文翻译：

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时分复用干涉式光纤传感器阵列中混叠噪声的分析与抑制


混叠噪声提高了脉冲触发时分复用 (TDM) 干涉光纤传感器阵列的最终噪声水平。在这里，我们首次提出基于干涉光纤传感器阵列的噪声功率谱密度分析的混叠因子的分析模型。与之前的报告相反，发现混叠因子不仅取决于脉冲宽度和重复频率，而且还取决于当应用匹配滤波器来抑制主瓣之外的噪声分量时脉冲的上升时间。该模型还表明了混叠因子和 TDM 通道数量之间的显式缩放规则。通过测量不同脉冲参数组合下的本底噪声，对该模型进行了实验验证。基于该模型，超低本底噪声为 -114 dB ref rad/Hz−−−√\sqrt{\mathbf {Hz}}（即 2 μ\boldsymbol{\mu}rad/Hz−−−√\ sqrt{\mathbf {Hz}}) 已实现，并且可以多路复用多达 6 个干涉式传感器，据了解，这代表了 TDM 干涉式光纤传感器阵列迄今为止的最低噪声水平。我们的结果揭示了脉冲上升时间对混叠噪声的显着影响，并提供了抑制 TDM 传感器阵列本底噪声的实用方法。