Interwavelength-band nonlinear interactions and their suppression in multiwavelength-band WDM transmission systems

We describe the effects of interwavelength-band nonlinear interactions, such as nondegenerate four-wave mixing, stimulated Raman scattering, and cross-phase modulation in multiwavelength-band WDM transmission systems. Through both numerical analysis and transmission experiments, these interactions are shown to cause serious degradation, especially when the walk-off between the utilized wavelength bands is small. Focusing on suppressing both these interwavelength-band nonlinear interactions and traditional intrawavelength-band nonlinear interactions, we present the guidelines for designing ultra wide-band WDM transmission systems over various types of fibers. The guidelines include band-by band bidirectional transmission, which offers large walk-off and minimizes the degradation caused by interwavelength-band nonlinear interactions. Finally, several dual-wavelength-band transmissions over dispersion-shifted fibers and standard single-mode fibers are demonstrated according to the guidelines.