摘要:
In order to transmit messages on an optical fiber (6), a multitude of message carrier channels (12) with different carrier frequencies, and a number of filling channels (13) are used that are transmitted together with the message carrier channels (12) over the fiber (6). The optical total power of the message carrier channels and of the filling channels is constantly held in that every change in power of the message carrier channels is compensated for by an opposite and equal change in the optical power of the filling channels. The change in the optical power of the filling channels is divided over the individual filling channels in such a manner that a minimal shifting of the center of the common spectrum of message carrier channels and of filling channels results.
摘要:
An output stage for carrying out WDM message transmission transmits both a number of carrier waves, which are modulated with a message signal, as well as a full light wave. A first control circuit (7-1) controls a set power signal that determines the power of the full light wave. The set power signal is controlled in such a manner that the total power of both the carrier waves and full light waves detected by a photodetector (9-1; 9-2) is constantly held to a predetermined reference value (REF). The full light source (4-1) is part of a subassembly (6-1), which is mounted in an exchangeable manner on a first mounting location inside the output stage. A subassembly (6-2) containing a second full light source (4-2) is mounted or can be mounted on a second mounting location of the output stage. An auxiliary circuit (7-2; 7-1) is provided for supplying one of the two full light sources (4-1, 4-2) with a continuously diminishing second set power signal.