Fiber Loop Ring Down Fault Detection With Centimeter-Level Spatial Resolution Based on Random Distributed Multiultrashort Pulse

We proposed a fiber loop ring down (FLRD) fault detection system with high spatial resolution using random distributed multiultrashort pulse (RDMUP). The RDMUPs are generated in a mode-locked fiber laser. We studied the random characteristics and autocorrelation function of RDMUPs. The narrower full width at half maxima of the autocorrelation function can achieve better spatial resolution for fault detection. So, we analyzed the RDMUP as the detection signal in the FLRD fault detection. The reflected light passed through the fault point achieves the position measurement of fault detection and the combination analysis of transmitted light and reflected light achieves the detailed loss by the ring down time of the peak of the autocorrelation function in the fiber loop cavity. The experimental results show that the distance-independent centimeter-level spatial resolution is realized, and the loss of the fault point is obtained at the same time. We believe that the proposed system has great potential in fault detection.