Patent ID: 6275316
Filing Date: 2001-08-14
Classification: H04B

Abstract:
A method of controlling and/or monitoring an optical transmission of message signals over an optical line, said optical line comprising at least one optical repeater station (40, 50) connected between optical wave guides (10), said method comprising the steps of:a) transmitting the message signals and optical secondary signals acting as monitoring and/or control signals over said optical line;b) receiving the optical secondary signals in said at least one optical repeater station (40, 50) from an upstream portion of said optical line;c) optically modulating said optical secondary signals received in step b) in said at least one optical repeater station (40, 50) to produce further optical secondary signals to be transmitted over a downstream portion of said optical line; andd) transmitting said further optical secondary signals over said downstream portion of said optical line;wherein no optical carrier signals are generated in said at least one repeater station (40, 50).