【作者】 张聪；

【导师】 余文峰；

【作者基本信息】 华中科技大学 ， 物理电子学， 2015， 硕士

【摘要】 光纤分布式传感技术是目前光纤传感领域的一种新型的传感技术,它具有抗电磁干扰、抗腐蚀、连续监测等优点,在实际的工业测量和监测中具有较大的应用价值。基于布里渊散射的光纤传感技术能够同时监测到温度和应变,并且是在连续空间上的点,但是具有一定的分辨率和测量精度。本论文对基于受激布里渊散射效应的光纤传感的原理和技术进行研究,主要分为以下几个方面:首先,通过瞬态方程并采用MATLAB进行数值计算,研究了瞬态下传感系统中抽运光和散射光的变化,得出传感系统中斯托克斯光产生受激布里渊散射的放大效应,并计算了散射光的功率变化特点,因此可以看出双光源系统受介质内部噪声影响比单光源系统要小。其次,分析了系统中的散射光的频域和时域特性,通过分析建立了脉冲宽度与布里渊散射频谱波形之间的关系,并表明脉冲宽度的增加使得频谱波形出现变化,从而为传感精度的控制提供参考;分析了散射光的时域特性,可知在脉冲光作用下产生的散射光具有脉冲特性,并且可知散射光具有提供基于布里渊散射的光时域反射(Optical time domain reflection,OTDR)定位的能力。这对于传感系统的性能改进具有帮助。最后,本论文通过Optisystem和MATLAB对布里渊光时域分析(Brillouin optical time domain analysis,BOTDA)系统进行仿真优化,结果表明改变直流探测光、入射光的频率偏移以及多脉冲都会影响到信号的信噪比,并且入射抽运光脉宽的改变不仅影响散射光的功率,还会影响散射光的谱宽度,这为传感信号的谱宽度、信号功率以及信噪比仿真优化提供了参考价值。更多还原

【Abstract】 Distributed fiber optical sensing technology is a new sensor technology, it has anti-electromagnetic interference, anti-corrosion, continuous monitoring, etc., and has great value in the actual industrial measurement and monitoring. Based on brillouin scattering, optical fiber sensing technology can simultaneously monitor the temperature and strain, and is the point on a continuous space, but it has a certain resolution and measurement accuracy. In this paper, the fiber optic sensing principles and technology based on stimulated Brillouin scattering effect are researched, which is divided into the following areas:Firstly,through the transient equation and MATLAB numerical calculation, the variation of pumping light and scattered light is researched in the transient sensing system.It is show that stokes light in sensing system produces stimulated brillouin amplification effect.The power variation characteristics of light scattering is calculated, so it show that double light source system by the medium effect of internal noise is smaller than the single source system. Secondly,in the system,the frequency domain and time domain characteristics of the scattered light are analyzed.The relationship between the pulse width and the Brillouin scattering spectrum waveform changes,and shows the pulse width increases,the spectral waveform changes,which is helpful for the sensing accuracy control; The time-domain of the characteristics of the scattered light is analyzed and it is seemed that the scattering light having a pulse characteristics under generated pulse light, and is found that the scattered light has the ability to provide the positioning of the OTDR based on the brillouin scattering,which is help for improving sensing system. Finally, BOTDA system performance is analyzed and simulated by Optisystem and MATLAB. The results show that the change of the DC probe, the incident light frequency offset and multi pulse will affect the signal to noise ratio, and then the incident pump power pulse width changes not only affect the scattering of light, but affect the scattering light spectrum width, which is helpful for the simulation optimization of sensing signal spectrum width, signal power and signal to noise ratio.更多还原