Analytical characterization of a quasi-lossless Raman-amplified fibre transmission scheme

In this paper, we explore theoretically a novel amplifier scheme, that combines second order bidirectional pumping and fiber Bragg grating reflectors to achieve quasi-lossless transmission over long spans. The scheme is shown to significantly reduce the signal power variation over the span as compared to commonly used schemes with the same number of pump sources. It is concluded that it can be practical to analyze a simplified system of three equations, obtained by neglecting noise terms, that would allow us to better understand the physical mechanisms and to find analytical estimates for the required pump power or the power variations along the fibre span