The device includes a first detector configured to detect, from received signal power, first fault parameters related to an occurrence of a first fault on this optical fiber. The device further includes a database configured to store the first fault parameters and a second detector configured to detect from the received signal power second fault parameters related to a restoration of a second fault on the optical fiber. The device further includes a comparator configured to compare the second fault parameters with the stored fault parameters and to decide that the fault is resolved if the first fault parameters most closely match the second fault parameters.