Numerical study of moderate distance high bit-rate alternating-amplitude soliton systems

We present a numerical investigation of alternating-amplitude soliton systems. We propagate 100 Gb/s, pseudorandom bit sequences of 2/sup 5/-1 to 2/sup 7/-1 solitons through fibers of different lengths and calculate the corresponding eye opening penalty at the receiver. The influence of different amplitude ratios, amplifier spacings, pulse widths, and dispersion slopes as well as of the soliton self-frequency shift are studied. We also study the effect of compression of the alternative-amplitude solitons with the larger amplitudes to preserve their soliton character and the impact of the relative initial phase between the alternating-amplitude solitons. When the amplifier spacing is 10 km the system length can be at least 400 km with alternating-amplitude solitons compared to only 200 km in the case of equal amplitude solitons with similar penalties. Our simulations show-that third-order dispersion and the soliton self-frequency shift limit the maximum allowable amplitude ratio.