Theory of Raman effect on solitons in optical fibre systems: impact and control processes for high-speed long-distance transmission lines

We examine the effects of stimulated Raman scattering on ultra-short pulses propagating in optical fibre systems. We demonstrate that the existing theories for the Raman-induced soliton self-frequency shift give consistent results in a restricted domain Of Pulse width which excludes important practical applications to high-speed soliton transmission systems. We present a general theory for the soliton self-frequency shift (SSFS), which applies to any pulse whose spectral bandwidth lies within the third-order telecommunication window. We also show that the harmful impact of the SSFS in high-speed long-distance transmission lines can be Suppressed by use of filters whose central frequency is appropriately up shifted with respect to the transmission frequency. (C) 2004 Elsevier B.V. All rights reserved.