搭建了一种新型的基于瑞利散射的布里渊光时域分析(Rayleigh Brillouin optical time domain analysis, RBOTDA)传感系统。该系统工作在单端, 能克服传统 BOTDA 双端接入的缺点; 采用两个EOM并联的结构产生含有连续基底光的脉冲光, 探测光由基底连续光的瑞利散射提供, 避免了多种受激布里渊散射(stimulated Brillouin scattering, SBS)作用带来的干扰, 信噪比更高, 传感距离更长; 采用双边带探测方法, 有效减少泵浦脉冲的损耗与非本地效应。建模解析了该系统中的SBS作用过程, 并实验验证了系统的可行性。结果表明, 布里渊增益谱完好地贴合洛伦兹曲线, 非本地效应得到了有效的抑制; 在2.4 km光纤上, 室温25 ℃下泵浦脉宽50 ns时, 布里渊频移为10.867 GHz, 布里渊线宽约为40.21 MHz。

A new type of distributed sensor system based on Rayleigh scattering Brillouin Optical Time Domain Analysis (RBOTDA) was proposed. This system was realized in one end access fiber, which can improve the shortcomings of two end access in conventional BOTDA. Parallel structure with two EOM were used to generate pulsed light with continuous base wave. Probe light was provided by the Rayleigh scattering of the base continuous light. This avoids the interference of a variety of Stimulated Brillouin Scattering (SBS) effect and brings the higher signal to noise ratio and longer sensing distance. The dual sideband probe scheme turns the system to be highly robust against pump pulse depletion and non-local effect. The SBS function mechanism of the system was analyzed and the feasibility of the proposed method was demonstrated experimentally. The results show that the Brillouin gain spectra fit Lorenz Curve perfectly and non-local effect is suppressed effectively. The Brillouin frequency shift is 10.867 GHz and the Brillouin linewidth is about 40.21 MHz with 50 ns pulse width on the 2.4 km optical fiber at the temperature of 25℃.