Phase-Sensitive Optical Time Domain Reflectometer Based on Phase-Generated Carrier Algorithm

作者：Fang, Gaosheng^*; Xu, Tuanwei; Feng, Shengwen; Li, Fang

来源：Journal of Lightwave Technology, 2015, 33(13): 2811-2816.

DOI：10.1109/JLT.2015.2414416

• Optical time domain reflectometer
• phase-generated carrier
• Rayleigh scattering

We propose a novel approach to generate distributed fiber sensing system based on phase-sensitive optical time domain reflectometer (Phi-OTDR) and phase-generated carrier demodulation algorithm. An unbalanced Michelson interferometer is introduced at the receiving end of the system. The back Rayleigh scattering light from a certain position along the sensing fiber would interfere to generate interference light signal versus time, whose phase carries the sensing information. Phase-generated carrier demodulation algorithm is proposed and carried out to recover the phase information. A single frequency vibration event is applied to a certain position along the sensing fiber and we realize to demodulate it correctly. The noise level of the phase sensitive OTDR system is about 3 x 10(-3) rad/root Hz and a signal to noise ratio about 30.45 dB is achieved. The maximum sensing length and the spatial resolution of the Phi-OTDR system are 10 km and 6 m with pulse repetition rate at 10 kHz and 6 m fiber delay in MI with interrogating pulse width of 30 ns.

• 单位
  中国科学院