Random coding method for coherent detection φ-OTDR without optical amplifier
Random coding method for coherent detection φ-OTDR without optical amplifier
复制标题
DOI：
10.1016/j.optlaseng.2022.107318
复制
发表时间：
2023-02
影响因子：
4.6
通讯作者：
Peihong Li;Yu Wang;Kang Yin;Xin Liu;Qing Bai;Hong-juan Zhang;Yang Gao;Bao-quan Jin
中科院分区：
文献类型：
--
作者：
Peihong Li;Yu Wang;Kang Yin;Xin Liu;Qing Bai;Hong-juan Zhang;Yang Gao;Bao-quan Jin
本文提出了一种不带光放大器的相干检测相敏光学时域反射计（φ-OTDR）。在光纤中注入一系列随机编码调制的脉冲，提高了信号的信噪比，延长了传感距离。该码只需要一个序列进行解码，保持了原有的感知带宽。同时，编码探针脉冲不经过任何光放大器，避免了瞬态效应。实验结果表明，采用128位随机编码脉冲后，解调信号的信噪比提高了14.19 dB。传统的掺铒光纤放大器（EDFA）单脉冲方案在25.521 km处，在40 ns脉宽处，强度信噪比仅为5.39 dB，振动信号无法有效解调。在相同脉宽的系统中，可以成功定位42.338 km处的外部干扰，解调信号的信噪比为21.5 dB。
In this article, a coherent detection phase-sensitive optical time-domain reflectometry (φ-OTDR) without optical amplifier using random coding method is proposed. A series of pulses modulated by random codes are injected into the optical fiber to enhance the signal-to-noise ratio (SNR) and extend the sensing distance. The code only needs one sequence for decoding, which maintains the original sensing bandwidth. Simultaneously, the coding probe pulse does not pass through any optical amplifier to avoid the transient effect. Experimental results show that the SNR of the demodulated signal is improved 14.19 dB by using 128-bit random coding pulse. In the traditional single pulse scheme with erbium doped fiber amplifier (EDFA), the intensity SNR at 25.521 km is only 5.39 dB with a 40 ns pulse width, and the vibration signal cannot be effectively demodulated. In the proposed system with the same pulse width, the external disturbance can be located successfully at 42.338 km, and the SNR of the demodulated signal is 21.5 dB.