Development of a Multiperimeter Sensing System Based on POTDR

Polarization optical time-domain reflectometry (POTDR) is sensitive to perturbations on any point of the fiber under test (FUT). However, restricted by the sensing principle, the signal of the front perturbation would mask the signals of the rear ones. Thus, in practical applications, a perturbation on the lead fiber between a POTDR and the FUT would generate unnecessary signal which hinders POTDR from distinguishing the valid signal. In this paper, a new POTDR scheme which is robust to perturbations on the lead fiber is proposed. So only the perturbations on the FUT can generate signals. The principle is explained in detail and experiments demonstrate the validity of this scheme. By using the proposed scheme, multiple perimeters are monitored independently at one time, and distributed sensing is realized for each perimeter.