基于布里渊损耗的单端分布式光纤传感系统研究

基于布里渊散射的分布式光纤传感系统以其可在整根光纤中同时得到被测量场在时间和空间上的连续分布信息,进而成为传感领域国内外研究的热点。针对传统的布里渊光时域分析分布式传感器只能双端入射且成本较高的缺陷,探索性地提出了一种新型的单端布里渊损耗光时域分析传感结构。采用一台窄线宽激光器作为唯一光源,应用铌酸锂电光强度调制器调制入射光产生频移可调的脉冲泵浦光,与经过光纤布拉格光栅反射的连续探测光进行布里渊散射放大效应。通过检测探测光光功率,采用洛伦兹和高斯函数线性权重谱和Levenberg-Marquardt算法得到了不同脉宽下整根光纤布里渊损耗谱。实验结果初步证明了这种传感结构对于分布式测量是可行的,对单端BOTDA的研制具有一定的供参考价值。

Study on single-ended distributed optic-fiber sensing system based on Brillouin loss

Distributed optical fiber sensing system based on Brillouin scattering has attracted a widely attention as it can simultaneously obtain the continuous distributed information of time and space in the measured field. A novel Brillouin optical time-domain analysis (BOTDA)sensing configuration is presented,called single-ended BOTDA system. A narrow line-width laser was used as the only light source,and LiNbO3 electro-optics intensity modulator was adopted to modulate tunable frequency shift pulse pump light generated by incident light,the pump light with detection light reflected by fiber Bragg grating (FBG)was carried out Brillouin scattering amplification. Through detecting optical power of detection light,Brillouin loss of the whole fiber was obtained with the different line-widths by linear weight spectrum of Lorentz and Gaussian function and Levenberg-Marquardt algorithm. Experimental results show the sensing structure is suitable to distributed measurement,and it has certain reference to the development of BOTDA.