Research on bidirectionally pumped Raman amplifiers: noise and transmission performance

Abstract

In this paper we investigate both noise and transmission performance of bi-directionally pumped Raman amplifiers (RAs) in longhaul WDM systems detailedly. Compared with backward pumping or Raman+EDFA hybrid amplification, bi-directionally pumping can provide flatter OSNR spectra in wideband WDM applications, as well as better noise performance at identical nonlinear phase shift due to its uniform power distribution. Moreover, transmission impacts induced by SPM and XPM are also analyzed, which indicates that Raman amplified systems are more sensitive to dispersion maps than discrete amplification.