Patent ID: 6580536
Filing Date: 2003-06-17
Classification: H04J

Abstract:
A wavelength division multiplexed (WDM) system comprisingat least one optical amplifier for amplifying optical wavelengths in at least two wavelength regions, each region exhibiting a different transmission gain level for all wavelengths within that region, where the optical amplifier has a gain in a first region that is higher than the gain in a second region; at least one first-type transmitter, each first-type transmitter transmitting an optical wavelength selected from the first region of said at least two regions and modulated at a data bit rate at or below a first data bit rate; at least one second-type transmitter, each second-type transmitter transmitting an optical wavelength selected from the second region of said at least two regions and modulated at a data bit rate at or below a second data bit rate, where the second bit rate is lower than the first bit rate; and wherein the first region is a flat-passband transmission region of the system having a gain level which falls within a predetermined range and the second region has a gain level outside that predetermined range in a roll-off region of the system gain level.