Ultrahigh-speed long-distance TDM and WDM soliton transmission technologies

Recent progress on time-division multiplexed (TDM) and wavelength-division multiplexed (WDM) soliton transmission is described, in which dispersion ma nagement (DM) plays an important role in increasing the power margin and th e dispersion tolerance. The characteristics of the DM soliton are compared with those of return-to-zero (RZ) and nonreturn-to zero (NRZ) pulses, With a small dispersion swing, the system can still he described as an average s oliton with a nonlinear Schrodinger equation (NLSE), whereas with a large d ispersion swing, the soliton-like steady-state pulse becomes a chirped Gaus sian pulse, in which the master equation is closer to a linear Schrodinger equation (LSE) with a parabolic potential well. An in-line modulation schem e up to 80 Gb/s per channel and its two-channel WDM transmission over 10 00 0 km are described. A 640-Gb/s (40 Gb/s x 16 channels) WDM soliton transmis sion over 1000 km is also reported with a DM single-mode fiber, without the use of in-line modulation. Finally, dark soliton transmission at 10 Gb/s o ver 1000 km is described as a different nonlinear pulse application.