Demonstration of Counter-Propagating Raman Pump Placed Near Signal-Channel Wavelengths

As optical-fiber capacity is increased by the use of multiple signal bands such as the combined S+C+L bands, signals in the S -band may have to co-exist with Raman pumps operating in nearby wavelength slots. We investigate the impact of placing a counter-propagating Raman pump near a 32-Gbd polarization-division-multiplexed 16-ary quadrature-amplitude-modulated signal.