Long-haul transmission using counter-pumped distributed Raman ring laser amplification

Abstract

This paper proposes a novel distributed Raman amplification (DRA) scheme for long-haul optical fiber transmission systems. The scheme utilizes two fibers for the bidirectional transmission links, and each fiber is counter-pumped by a second-order pump source. The first-order pump lights are generated in the ring cavity consisting of two fibers, and amplify the optical signal. This scheme enables both co-pumping and counter-pumping from the generated first-order pump lights by using only second-order counter-pumping. The amplification performance of the proposed scheme is examined in the long-haul transmission experiments using dual-polarization QPSK signal, and the proposed scheme is confirmed to improve the transmission performance compared with the conventional first-order counter-pumping DRA.