Transparency in optical networks

Besides transparency criteria for the conventional parameters of the light-signals in an optical network the transparency with respect to the outstanding optical capacity based on the fundamental theory of Shannon is investigated for optical communication links. It is calculated that the wavelength window between 1.3 and 1.6 mu m is transparent for 320 Tbit/s as an upper bound which can be approached by proper optical frequency multiplexing techniques. The principal constraints of fibre length, amplifiers and switching nodes placed on the capacity resulting in a reduction of transparency are outlined and the design for a high transparent frequency switching matrix is presented.