Liu Can, Yan Lianshan, Li Zonglei, Zhou Yin, He Haijun, Pan Wei, Luo Bin
Opt Express. 2022 Mar 28;30(7):11306-11316. doi: 10.1364/OE.452762.
Conventional Brillouin optical time-domain analyzer (BOTDA) with a frequency-modulated probe (FMP) could avoid non-local effects, while still suffering from the acoustic crosstalk between different frequencies. The induced Brillouin frequency shift (BFS) measurement errors over the whole sensing fiber link reduce system certainty subsequently. A BOTDA scheme with a bidirectional frequency-modulated probe (BFMP) is proposed to overcome such an effect. It utilizes BFMP to generate the crosstalk of the same magnitude and opposite direction to compensate each other. Experimental results indicate that the pulse interval of the coded sequence could be reduced to ∼500 ns to improve the measurement efficiency and BFS estimation errors (∼2.2 MHz) over 117.46-km sensor link are eliminated simultaneously.
采用调频探针（FMP）的传统布里渊光时域分析仪（BOTDA）可以避免非本地效应，但仍会受到不同频率之间的声学串扰影响。整个传感光纤链路上的布里渊频移（BFS）测量误差会降低系统的确定性。为克服这一效应，提出了一种采用双向调频探针（BFMP）的BOTDA方案。该方案利用BFMP产生大小相等、方向相反的串扰以相互补偿。实验结果表明，编码序列的脉冲间隔可减小至约500 ns，以提高测量效率，同时消除了117.46 km传感器链路上的BFS估计误差（约2.2 MHz）。
