title: Investigation and optimization of bidirectionally dual-order pumped distributed Raman amplifiers.
abstract: A theoretical investigation of bidirectionally dual-order pumped distributed Raman amplifiers is presented in detail, and comparisons with other Raman amplification schemes, i.e., bidirectional first-order pumping and Raman-plus-erbium-doped fiber hybrid amplification, are carried out, for the first time to the authors' knowledge, at identical nonlinear phase shifts. The results show that symmetric bidirectional dual-order pumping can achieve the best optical signal-to-noise ratio performance by appropriate choice of the second-order pump wavelength and second-to-first-order pump power ratio for both short- and long-span conditions, which will be helpful for designing long-haul transmission systems.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Tong
authors.forename: Huai
authors.initials: H
authors.lastname: Wei
authors.forename: Shuisheng
authors.initials: S
authors.lastname: Jian