Patent ID: 7885539

Claim:
A method for detecting faults in a transmission path, having at least one optical fiber, of an optical transmission system, comprising: injecting light having an input state of polarization into the transmission path at a first location of the transmission path; decoupling the light at a second location of the transmission path, the first and second locations being spaced apart from each other so that the light decoupled at the second location has passed through at least one section of the transmission path; measuring a state of polarization of the decoupled light in a manner resolved as to time; determining a temporal change in the state of polarization of the decoupled light; detecting an external influence on the optical fiber in response to the temporal change in the state of polarization of the decoupled light; and evaluating using an evaluation device connected to at least two polarimeters, a time function of a respective state of polarization at each of the at least two polarimeters is compared in order to assign a corresponding signal to a specific fault, where a location of the specific fault is calculated using: s 1 = S - ( t 2 - t 1 ) ⁢ ⁢ c n 2 where S 1 is a path section between one of the at least two polarimeters and the fault, S is a distance between the at least two polarimeters, t 2 −t is a difference in arrival times between the at least two polarimeters, and C n is a propagation speed of the light in a transmission medium.