Yes, I am trying to implement WDM PON system using RSOA, for a paper. But before I do that, I wanted to see how RSOA behave. I wanted to remodulate the upstream signal with RSOA, but as I proceeded, The BER was not that good. I also tried varying some of the parameters of RSOA, like the Facet reflectivities and active length, But a good result was not obtained.