Liu Can, Yan Lianshan, Zhou Yin, He Haijun, Pan Wei, Luo Bin
Opt Express. 2021 Aug 16;29(17):27340-27349. doi: 10.1364/OE.434519.
The erbium-doped-fiber-amplifier (EDFA), generally served as a pre-amplifier, could effectively raise the signal-to-noise ratio (SNR) of a Brillouin optical time-domain analysis (BOTDA) sensor. However, it also induces a distortion in the Brillouin gain spectrum and Brillouin frequency shift measurement errors due to the slow transient effect (STE) in the coded-BOTDA. We propose a distributed depletion mapping (DDM) method to overcome such an effect. A continuous light wave with a particular wavelength is injected to map the STE-induced depletion to compensate for the distortion. The proposed scheme is experimentally demonstrated along a 120-km sensing fiber with 2-m spatial resolution. Experimental results show that the conventional tail-alignment (TA) method cannot compensate for the STE over the whole fiber link, while the proposed DDM method compensates for over 7.69-MHz measurement errors.
掺铒光纤放大器（EDFA）通常用作前置放大器，可有效提高布里渊光时域分析（BOTDA）传感器的信噪比（SNR）。然而，由于编码BOTDA中的慢瞬态效应（STE），它也会在布里渊增益谱中引起失真以及布里渊频移测量误差。我们提出了一种分布式损耗映射（DDM）方法来克服这种效应。注入特定波长的连续光波以映射由STE引起的损耗，从而补偿失真。沿着具有2米空间分辨率的120公里传感光纤对所提出的方案进行了实验验证。实验结果表明，传统的尾部对齐（TA）方法无法在整个光纤链路上补偿STE，而所提出的DDM方法可补偿超过7.69兆赫兹的测量误差。
