Analytical Model of Brillouin Scattering Spectrum Measurements in Fibre-Optic Distributed Sensing Systems
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摘要: 分析了当注入普通单模光纤的调制光脉冲宽度接近或小于10 ns时,由调制脉冲光和调制器泄漏连续光共同作用所产生的光纤分布式布里渊散射谱特性.在此基础上,建立了由洛伦兹(Lorentzian)型谱和高斯(Gaussian)型谱线性权重优化组合而成的光纤分布式布里渊传感散射谱数据拟合与参数估计Pseudo-Voigt(P-V)分析模型.利用该P-V模型和Levenberg-Marquardt(L-M)非线性最小二乘算法,对光纤布里渊散射谱采样数据进行了曲线拟合和最优化参数估计.结果表明,与Lorentzian型谱或Gaussian型谱相比,用P-V模型处理传感散射谱数据,数据拟合程度更好,参数估计精度更高.
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关键词:
- 光纤分布式传感 /
- 布里渊散射谱 /
- Pseudo-Voigt型曲线 /
- L-M算法
Abstract: Under the condition that the pulse widths are near or below the photon lifetime,i.e.10 ns,scattering spectrum properties of fibre-optic distributed sensing systems were analyzed and discussed.A nonlinear Pseudo-Voigt(P-V) analytical model was established by optimal combination of Lorentzian and Gaussian profiles for Brillouin scattering spectrum in fiber-optic distributed sensing systems.The P-V model and the Levenberg-Marquardt(L-M) nonlinear least square algorithm were applied to curve fitting and optimal parameter estimation of measured data of Brillouin scattering spectrum.Better fitting and higher resolution for parameter estimation were obtained with the proposed method compared to the conventional Lorentzian and Gaussian profiles. -
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