A distributed optical fiber sensor system for intrusion detection and location based on the phase-sensitive OTDR with remote pump EDFA

Abstract In this paper, a distributed optical fiber senor system for multi-intrusion monitoring has been proposed along a 25 km distance based on phase-sensitive optical time domain reflectometer ( Δ t = 100 n s ) and a remote optically pump amplifier (ROPA). The ROPA is based on Raman pump relay free amplification and remote connected in erbium-doped fiber (EDF). It makes the detection distance increase 108%, from 12km to 25km. The best amplification effect is achieved when the EDF is connected in the middle area. In the experiments, several vibrations of the fiber at different locations given by piezoelectric transducers (PZTs) simulate the vibrations caused by intrusions. Three remote intrusions have been detected and located simultaneously along a 25km optical fiber with a spatial resolution of 10m. In order to improve the signal-to-noise ratio (SNR) and detection distance, the semiconductor optical amplifier (SOA) with high extinction ratio and narrow pulse width has been used to modulate light into pulses. The SNR of 9.5dB has realized for intrusion detection at remote tail end of 25km distance. The experimental results can be the references for improving the remote intrusion detection and location technology of Φ − O T D R sensor system.