Patent ID: 7187868

Claim:
A method of optical transmission in a WDM system comprising an optical link (OL), said optical link comprising at least a first and a second optical path, said first optical path comprising at least a first section and a second section, said method comprising the steps of: (a) transmitting along said first section of optical path a series of optical channels comprising at least a first plurality of optical channels experiencing, in said first optical path, a first plurality of average dispersion values having the same sign as each other; (b) compensating, at least partially, the dispersion accumulated by said first plurality of channels in said first section along said second section of optical path; (c) at the end of said first optical path, inverting spectrum and modifying wavelengths of said first plurality of optical channels in such a way as to obtain a second plurality of optical channels, experiencing, in said second optical path, a corresponding second plurality of values of average dispersion having the same sign as the values of average dispersion of said first plurality of average dispersion values, wherein said series of optical channels comprises at least a third plurality of optical channels experiencing, in said first optical path, a corresponding third plurality of values of average dispersion having the opposite sign to the values of average dispersion of said first plurality of average dispersion values; (d) transmitting the second plurality of optical channels along said second optical path; (e) separating the channels of said first plurality from the channels of said third plurality, in a third and a fourth optical path respectively, before said step of inverting the spectrum, wherein said third optical path comprises a first conversion device and the fourth optical path comprises a second conversion device; (f) inverting the spectrum and modifying the wavelengths of said third plurality of channels in said second conversion device in such a way as to produce a fourth plurality of channels, experiencing a corresponding fourth plurality of values of average dispersion which, in said second optical path, have the same sign as the values of average dispersion of said third plurality of values of average dispersion; (g) combining said second and said fourth plurality of channels in said second optical path; and (h) transmitting said fourth plurality of channels along said second optical path.