Intra-Channel Cross-Phase Modulation and Four-Wave Mixing in High-Speed TDM Systems

A comprehensive numerical and experimental study of 40 Gb/s transmission is revealing two new forms of nonlinear interactions limiting high-speed systems. Both limitations originate from nonlinear interactions among neighboring pulses from the same channel. The first interaction involves cross-phase modulation and leads to timing fluctuations while the second interaction originates from four-wave mixing and leads to creation of new pulses appearing in the "zeris" slots as well as amplitude jitter of the "ones" pulses. Both phenomena are bit-pattern dependent.