Patent ID: 6690886
Filing Date: 2004-02-10
Classification: H04B,H04J

Abstract:
A bidirectional optical wavelength division multiplexed (WDM) transmission system for connecting between a first node having a first multiplexer and a first demultiplexer and a second node having a second multiplexer and a second demultiplexer, the system comprising a transmission link between the two nodes, the transmission link comprising a plurality of lengths of optical transmission fibres, including one at each end of the link, and a plurality of first dispersion compensating modules (DCMs) and amplifiers located between individual pairs of the length of optical transmission fibres, a first optical branching device connecting one end of the transmission link to the first multiplexer and, through a second DCM and a serial third DCM, connecting the one end also to the first demultiplexer, a second optical branching device connecting another end of the transmission link to the second multiplexer and, through a fourth DCM and a serial fifth DCM, connecting the another end also to the second demultiplexer,wherein the properties of the first, second and fourth DCMs are selected to suppress four-wave mixing rather than to provide complete chromatic dispersion compensation and wherein the properties of the third and fifth DCMs are selected to substantially complete chromatic dispersion compensation over the total length of the link.