Continuous measurement of distributed vibration using coherent Rayleigh backscattering

摘要

The detection of external vibration with optical pulses is the discrete sampling in phase-sensitive OTDR. In this paper, the continuous measurement of distributed vibration based on the phase-sensitive OTDR is demonstrated. The synchronized optical signal consisting of narrow optical pulses and the background light is injected into the sensing fiber as probe light. The time-resolved disturbance is continuously recorded by the background optical signal. The detectable frequency response range and the accuracy of the signal reconstruction are improved. The Rayleigh backscattering light generated by the background optical signal interferes at the detection end, presenting an enhanced sensitivity to external vibrations. The Rayleigh backscattering of narrow pulses is tracked to locate vibrations. The system can realize continuous measurement of distributed vibration with enhanced frequency response range and sensitivity.