| Abstract: | In an ideal continuous exponential varying-dispersion fiber, black solitons, like their bright counterparts, can propagate over long distances without being broadened when the weakened nonlinearity that is due to the fiber loss is compensated for by the decreasing dispersion. It is found, however, that in a practical stepwise decreasing-dispersion fiber with N steps the number of steps N required for well-behaved evolution of black solitons in a lossy fiber with negligible distortion and broadening is fewer than for bright solitons. This finding indicates that the stepwise-varying-dispersion in fibers can be more effective for extending the amplifier spacing or reducing amplifier numbers in the high-bit-rate black soliton transmission system than in the corresponding bright soliton transmission system. |
