Analyses of variations of non-degenerated four-wave mixing between co-pump Fabry-Perot modes and signal in a non-zero dispersion shifted fiber

We theoretically and experimentally study of the four-wave mixing (FWM) between co-propagated pump and signal in a distributed Raman amplifier (DRA) over a 25 km of non-zero dispersion shifted fiber (NZDSF) with zero dispersion wavelength of 1495 nm. The 100 mW pump Fabry-Perot (FP) spectra centered at 1440 nm is reproduced via FWM around the single-wavelength probe signal around 1550 nm. The maximum FWM generated power ratio is found in the matching of the group delay between the signal and the two adjacent modes with larger powers in the pump Fabry-Perot laser diode. The zero-dispersion wavelength of NZDSF can also be determined at the middle of the center wavelength of pump and signal waves where maximum FWM occurs at minimum phase mismatching between two 14xx nm FP pump wavelengths and two 15xx nm signal wavelengths.