Two-pump fiber OPAs with flat gain over 100 nm bandwidth

In this paper we review recent experiments where well designed highly nonlinear fibers (HNLFs) give rise to flat gain over 115 nm is, also we discuss the feasibility of broadband two-pump optical parametric amplifiers (2P-FOPAs). It is believed that further improvements in designing and fabrication of HNLFs could result in 2P-OPAs with more than 200 nm. However, there is still one factor that we observed enhanced the gain ripple, and this is a phase mismatch introduced by the real part of the Raman susceptibility. Nevertheless, it was observed that the amount of gain ripple introduced by this effect varied from fiber to fiber.