Spectra and influences of Rayleigh backscattering (RB) and stimulated Brillouin scattering (SBS) in the fiber-optic distributed disturbance sensor (FDDS) were investigated. Models of RB, double RB (DRB) and SBS in long fibers were established. By numerical simulation, it was found that optical signal-to-noise ratio is extraordinarily reduced due to SBS and RB,which results in location errors. Numerical results were confirmed by experiments and helpful to improving the location precision for applications with long monitored length.%针对光纤分布式扰动传感器长距离应用定位误差增大的问题,研究了传感器长距离光纤中的瑞利散射和受激布里渊散射的光谱特性及其对系统定位精度的影响.建立了长距离光纤中瑞利和受激布里渊散射的数学模型,通过仿真研究发现散射光波的杂波干涉和强度噪声会严重降低干涉仪的光学信噪比,从而导致定位误差.通过实验验证了仿真结果的正确性.研究结论可以为提高长距离应用定位精度提供理论指导.
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