Investigation of in-line distributed Raman amplifiers with co and counter-propagating pumping schemes

The main goal of this paper is to investigate and compare the performance of an in-line distributed Raman amplifiers in cases of co and counter propagating pumping radiation in respect to the propagation direction of the amplified signal. The performance analysis is based on the results obtained in a 16 channel 10 Gbps dense wavelength division multiplexed optical transmission system with 50 GHz channel spacing, non-return-to-zero intensity on-off keying modulation format, and an in-line DRA was introduced. The main requirement that was set by the authors was that the power of the pump should not exceed 1 watt. While configuring the in-line DRA wavelength of the pumping radiation and the positioning of the amplifier chosen for both co and counter-propagating pumping schemes.