Wang Feng, Zhu Chenghao, Cao Chunqi, Zhang Xuping
Opt Express. 2017 Feb 20;25(4):3504-3513. doi: 10.1364/OE.25.003504.
We implement a BOTDR sensor that combines the complementary coding with the fast Fourier transform (FFT) technique for high-performance distributed sensing. The employment of the complementary coding provides an enhanced signal-to-noise ratio of the sensing system, which leads to high accuracy measurement. Meanwhile, FFT technique in BOTDR is combined to reduce the measurement time sharply compared to the classical frequency sweeping technique. In addition, a pre-depletion two-wavelength probe pulse is proposed to suppress the distortion of the coding probe pulse induced by EDFA. Experiments are carried out beyond 10 km single-mode fiber, and the results show the capabilities of the proposed scheme to achieve 2 m spatial resolution with 0.37 MHz frequency uncertainty which corresponds to ∼0.37 °C temperature resolution or ∼7.4 με strain resolution. The measurement time can be more than tens of times faster than traditional frequency sweeping method in theory.
我们实现了一种将互补编码与快速傅里叶变换（FFT）技术相结合的布里渊光时域反射仪（BOTDR）传感器，用于高性能分布式传感。互补编码的应用提高了传感系统的信噪比，从而实现高精度测量。同时，BOTDR中的FFT技术与经典扫频技术相比，大幅缩短了测量时间。此外，还提出了一种预耗尽双波长探测脉冲，以抑制掺铒光纤放大器（EDFA）引起的编码探测脉冲失真。在超过10 km的单模光纤上进行了实验，结果表明该方案能够实现2 m的空间分辨率，频率不确定度为0.37 MHz，对应约0.37 °C的温度分辨率或约7.4 με的应变分辨率。理论上，测量时间比传统扫频方法快数十倍以上。
