SUPPRESSION OF SOLITON JITTER BY A COPROPAGATING SUPPORT STRUCTURE

A new way to suppress the soliton's jitter in long-haul optical commun ication systems is proposed that does not use in-line filters. Paralle l to the information-carrier soliton stream, a periodic stiff array (c onsisting of bright or dark solitons) is launched in another mode, whi ch may be either an orthogonal polarization or, more realistically, an other wavelength. This support array induces, through the cross-phase modulation, an effective potential pinning of the signal solitons. Mos t promising is the scheme in which the support structure is an array o f dark solitons (while the information is carried by the bright ones). In the analytical part of the work we derive a Langevin equation for the information soliton in the presence of the induced potential and o f a random force representing the jitter, for both cases when the supp ort channel has anomalous or normal dispersion. Next, we derive the co rresponding Fokker-Planck equation. A solution to this equation explic itly demonstrates a strong suppression of the jitter in comparison wit h the Gordon-Haus limit. To check this mechanism directly we perform n umerical simulations of the coupled nonlinear Schrodinger equations fo r the information and support channels, including the jitter-generatin g random perturbations acting in both of them. The simulations demonst rate that, while in the absence of the support structure the soliton's jitter is growing in accord with the Gordon-Haus law, the support str ucture strongly suppresses the jitter, as is predicted by the analysis . (C) 1997 Optical Society of America [S0140-3224(97)01412-4].