Network element comprising • at least one first input, to which an optical input signal can be supplied, • at least one first output, which is adapted to emit an optical output signal, wherein • the Network element also contains a first coupler, comprising an input and a first output and second output, the first input of the Network element being coupled to the input of the first coupler, and • the Network element further contains an optical receiver, which has at least one input and at least one output, the second output of the first coupler being coupled to the input of the optical receiver, • the Network element further contains an optical transmitter, which has at least one input and at least one output, • the Network element further contains a signal processing device having at least one first input and at least one first output, the output of the optical receiver being coupled to the input and the input of the optical transmitter being coupled to the output, • the Network element further contains a second coupler, having a first input, a second input and an output, the first output of the network element being coupled to the output of the second coupler, the first input of the second coupler being coupled to the first output of the first coupler, and the second input of the second coupler being coupled to the output of the optical transmitter, characterized in that • the signal processing device is adapted to provide at the output thereof a signal which is formed in such a way that it contains a signal component which in the case of interference with the optical input signal cancels a channel in the optical output signal in the second coupler. • at least one first input, to which an optical input signal can be supplied, • at least one first output, which is adapted to emit an optical output signal, wherein • the Network element also contains a first coupler, comprising an input and a first output and second output, the first input of the Network element being coupled to the input of the first coupler, and • the Network element further contains an optical receiver, which has at least one input and at least one output, the second output of the first coupler being coupled to the input of the optical receiver, • the Network element further contains an optical transmitter, which has at least one input and at least one output, • the Network element further contains a signal processing device having at least one first input and at least one first output, the output of the optical receiver being coupled to the input and the input of the optical transmitter being coupled to the output, • the Network element further contains a second coupler, having a first input, a second input and an output, the first output of the network element being coupled to the output of the second coupler, the first input of the second coupler being coupled to the first output of the first coupler, and the second input of the second coupler being coupled to the output of the optical transmitter, • the signal processing device is adapted to provide at the output thereof a signal which is formed in such a way that it contains a signal component which in the case of interference with the optical input signal cancels a channel in the optical output signal in the second coupler.