The beam propagation method has been applied to determine the behavior of ultra short optical pulses in the lossy guides. The influence of pulse separation and different amplitude ratios on the soliton propagation is described. In the paper 500 Gbps soliton transmission over 30 km without pulses regeneration is described.
"Nonlinear optical fiber in local networks", Proc. SPIE 3731, Optical Fibers and Their Applications VI, (14 May 1999); doi: 10.1117/12.348713; https://doi.org/10.1117/12.348713