Patent ID: 7593608

Claim:
In an optical transmission system including: an optical transmitter for transmitting a plurality of independent wavelength channels; at least first and second spans, each said span respectively including: at least a first length of transmission optical fibre characterized by a positive dispersion coefficient; and at least a first length of dispersion-compensating optical fibre disposed after said length of transmission fibre and characterized by a negative dispersion coefficient for substantially compensating a large proportion of the group velocity delay accumulated by said wavelength channels in said first span; a first node module disposed after said first span including: an optical amplifying module; and a phase manipulation module for: a. substantially compensating for dispersion of said wavelength channels accumulated in said first span; b. substantially compensating for the remaining accumulated group delay in selected pairs of first and second wavelength channels; and c. modifying the phase of said second wavelength channel in said selected pair such that the cross talk between said selected pair of channels generated in the first link is at least partially compensated in the second link.