40 Gb/s WDM-transmission with EDFAs in comparison to Raman amplified transmission with Raman fiber lasers as first-order and second-order pump

We investigated a 16/spl times/40 Gb/s long-haul transmission to prove whether Raman fiber lasers can replace LDs used for codirectional second-order pumped Raman amplifiers (RA) and compared the RA to counter pumped RA and EDFAs.