Abstract

It is now well established that distributed and lumped (also referred to as “discrete”) Raman amplifiers improve WDM long-haul system performance by increasing system bandwidth, reach, and bit-rate.¹ As Raman gain occurs over long lengths of fiber, significant build-up of multi-path interference noise (MPI) in fiber might occur and create an additional system penalty.^2–4 MPI is forward scattered power caused by several sources: double Rayleigh back-scatter (DRBS), splice/connector reflections combined with single Rayleigh scattering, and double reflections. Of these, DRBS is the dominant contributor to MPI for most transmission link configurations.

© 2002 Optical Society of America