MULTILEVEL SOLITON COMMUNICATION-SYSTEM

A multilevel soliton communication system is proposed and assessed. In this system, at the transmitter end each channel transmits its data v ia fundamental solitons with a prespecified amplitude (i.e. soliton wi dth). At the receiver end we take advantage of the sensitive relations hip between the amount of fundamental soliton self-wavelength shift an d the width of the soliton in the subpicosecond region. We first compr ess the incoming soliton pulses to the subpicosecond level and pass th em through a short length of fiber at the end of which the pulses have become separated in the wavelength domain since each soliton, corresp onding to a data channel, has experienced a different Raman self-wavel ength shift. The channels are then easily separated by optical fitters . We have derived the design constraint relations for such a system. W e have then heuristically designed a 40 Gbs (four channels) system for a 1000 km propagation distance (total data-rate distance product of 4 0 Tb/km). Numerical simulations and noise analyses have verified the f easibility and practicality of the proposed system with very good desi gn margins. The wavelength jitter is found to be much smaller than the desired filter spacing, and thus its contribution to the bit error ra te is negligible. We also argue that the system is more tolerant to Go rdon-Haus timing jitter than conventional TDM soliton systems. The sys tem is all fiber and is, therefore, very cost effective as it does not require sophisticated electrooptic and microwave circuits for demulti plexing. The system can potentially operate at much higher speeds than those achievable in conventional soliton systems and it can be used i n parallel with WDM soliton system.