脉冲预泵浦瑞利BOTDA系统的瞬态解析方法

为了解决空间分辨率和频率测量精度之间的矛盾,将脉冲预泵浦的概念引入瑞利布里渊光时域分析系统,建立了运用瞬态受激布里渊散射耦合波方程组描述该系统的数学模型。采用时域有限差分法求解了瞬态受激布里渊散射耦合波方程,仿真拟合了常微分方程组的时域幅值解,并实验验证了脉冲预泵浦瑞利布里渊光时域分析系统散射光功率谱和理论的一致性。结果表明,传感脉冲光、瑞利散射光和声波场三波幅值拟合方程的均方根误差可达0.003 097、0.005 717和0.020 75,沿光纤长度该系统功率谱呈现出携带布里渊信息的瑞利散射特性,可实现光纤温度和应变的传感检测。

Transient analysis method of pulsed pre-pump Rayleigh BOTDA System

In order to solve the contradiction between spatial resolution and frequency accuracy, the concept of pulsed pre-pump is introduced into Rayleigh Brillouin optical time domain analysis system. This mathematical system model is established by using the transient stimulated Brillouin scattering coupled wave equations. The transient stimulated Brillouin scattering coupled wave equations are solved by using the finite difference time domain method. The amplitude solutions of the ordinary differential equations in time domain are fitted by simulation, and the conformity of the pulsed pr-pump Rayleigh Brillouin optical time domain analysis and theory is verified by experiment in the scattered light power spectrum. The results show that the mean square errors of the three wave amplitude fitting equations of the sensing pulse light field, Rayleigh scattering light field and the acoustic field can reach 0.005717,0.003097 and 0.02075. The power spectrum of this system is carried on the Rayleigh scattering characteristic of Brillouin information along the length of the fiber. And the sensing detection can be achieved for the temperature and strain changes in the optical fiber.