基于多相位编码调制的相位敏感光时域反射计研究OA

To overcome the trade-off between long sensing distance and high spatial resolution in phase-sensitive optical time domain re-flectometry(Φ-OTDR),a multivariate phase encoding modulation Φ-OTDR is proposed.The discrete sampling process has been ana-lyzed and the modulation and demodulation control strategy has been designed.By leveraging the principles of pulse time domain com-pression,a match filter system has been constructed,which allows for adjusting encoding parameters to achieve enhancement of pulse compression performance.Experimental results demonstrate that,compared to conventional single-pulse modulation methods,the signal-to-noise ratio at the end of the 20.4 km optical fiber is significantly extended to from 10.3 dB to 43.5 dB at 3.8 m spatial resolution,and the signal-to-noise ratio at the end of the 95.6 km optical fiber can still reach 12.1 dB,and it is able to accurately locate the vibration position and achieve phase recovery.The proposed method realizes the long distance sensing the Φ-OTDR system under high space res-olution,providing new solution rhtought for further improving the sensing capability of Φ-OTDR.