Analytical model for Raman noise figure in dispersion-managed fibers

We derive an exact and a closed-form approximate analytic formula for effective lumped Raman noise figure in backward-pumped dispersion-managed fibers (DMFs) of arbitrary topology. Within the single-pump small-signal amplification model, important effects such as unequal loss coefficients at pump and signal wavelengths or splice loss for the pump and the signal between the DMFsʹ sections are taken into account. Theoretical results agree well with the noise figure measured in a symmetric DMF. The developed approach can be used to optimize the noise performance of DMFs.