Layer-independent OTDR technology application based on correlation in a branched fibre optic network during operation

摘要

In a branched optical fibre network in which an optical signal (I) modulated with a data signal is distributed by a transmitter connected to the network, OTDR based on correlation is applied independently of position by uncoupling both a signal part (I1) of the distributed signal (I) in the forward direction and a signal part (R1) of the reflected signal (R) in the return direction at an arbitrarily chosen uncoupling point P in a fibre connection (46) of the network, detecting them and correlating them with one another. A device for performing such a positionally independent correlation OTDR is provided with uncoupling means (60) having a first signal output (68) and a second signal output (66), via which outputs the signal part (I1) and the signal part (R1), respectively, are fed to optical receivers (70 and 71). The signal parts received are detected by the receivers, demodulated and corresponding electrical signals are supplied to a correlator (78) which produces an OTDR signal for an OTDR imaging means (82). IMAGE