对于普通单模光纤的布里渊散射光,其频移是温度或应变的函数,因此通过检测光纤散射光信号的布里渊频移率,即可得到沿光纤一维分布的温度或应变。布里渊光时域分析(BOTDA)仪适合于长距离分布式传感,但存在受激布里渊散射信号的偏振相关性问题,会造成探测信号随偏振状态的随机波动,因此难以得到稳定的布里渊光频移信息。采用正交偏振控制对参与受激布里渊散射的激励和探测光信号进行偏振处理,抑制了受激布里渊散射的偏振相关性,通过检测探测光信号得到了布里渊散射光频移。最后实现了25 km普通单模光纤的分布式传感,在5 m空间分辨率下分别达到2 ℃的温度分辨率和30 με应变分辨率。

For the standard single-mode optical-fiber,the frequency shift of Brillouin scattering light is the function of the temperature or strain. So,the temperature or strain of the optical-fiber can be obtained,when Brillouin frequency shift is able to be detected. Brillouin optical time-domain analyzer (BOTDA) is suitable for long-distance distributed sensing,but the stimulated Brillouin scattering is polarization related,which makes it hard to stably detect the Brillouin optical frequency shift. A method named with the orthogonal polarization control is adopted to reduce the effect of the optical-polarization-related problem. A laboratorial system of 25 km distributed Brillouin optical time-domain analyzer is achieved,with 2 ℃ in temperature resolution,30 με in strain resolution,and 5 m in spatial resolution.