We compare techniques using two fibers connected either in series or in parallel for cancelling cross talk that is due to stimulated Raman scattering in wavelength-division-multiplexed systems. Theory shows that such cross talk can be completely eliminated by a series arrangement in lossy dispersionless fibers by means of midway amplification and spectral inversion. In dispersive fibers, cross-talk reduction of the order of the Raman gain G can be obtained by adding dispersion compensation and alternating dispersion. Alternatively, a similar cross-talk reduction can be obtained by use of parallel transmission of signals on different sets of wavelengths and differential detection; in the presence of dispersion, the dispersion for the different sets of wavelengths must be opposite. The parallel approach appears to be more practical.
© 1998 Optical Society of America
(060.2310) Fiber optics and optical communications : Fiber optics
(060.4510) Fiber optics and optical communications : Optical communications
(190.0190) Nonlinear optics : Nonlinear optics
(290.5860) Scattering : Scattering, Raman
M. E. Marhic, F. S. Yang, and L. G. Kazovsky, "Cancellation of stimulated-Raman-scattering cross talk in wavelength-division-multiplexed optical communication systems by series or parallel techniques," J. Opt. Soc. Am. B 15, 957-963 (1998)