Marked increase in power margin through the use of dispersion-allocated soliton and evaluation of transmission characteristics using Q map: Comparison between D-A soliton, NRZ pulse, and RZ pulse at zero GVD

When fiber routes for optical soliton transmissions are dispersion allocated, higher order solitons cannot be formed even at power levels reaching the higher-order soliton power determined by the average dispersion, since the group velocity dispersion (GVD) in the individual fiber is large and the phase matching necessary to form higherorder solitons cannot be obtained. Therefore, solitons with intensity higher than that of N = 1 can still be propagated with a simple and clean pulse waveform without splitting. In this paper, it is first shown that the power margin of the dispersion-allocated (D-A) soliton is 6-9.5 dB larger than that of the soliton with a uniform GVD. Next, a new method (Q map method) for the evaluation of optical transmission systems using the Q value is described, which indicates the signal-to-noise ratio of the received eye pattern. By using this method, the power margins and dispersion tolerances of the soliton, NRZ, and zero-dispersion RZ pulse transmissions are discussed and it is found that the D-A soliton transmission has the highest power margin.