Active Gain-Tilt Equalization by Preferentially 1.43 µm- or 1.48 μm-Pumped Raman Amplification

We have demonstrated the active tilt equalizer for reducing the power deviation among WDM signals by Raman amplification of the transmission fiber, which attached in front of an inline EDFA. We had employed 1.43 µm and 1.48 µm pump wavelength for Raman amplification, which offered the both positive and negative gain slopes in WDM bandwidth (1535-1561 nm). By controlling the pump power ratio betwee 1.43 µm and 1.48 µm, the power deviation of 5.0 dB in 32 WDM signals was reduced to 1.5 dB, and the effective noise figure of the EDFA was improved from 6.9 dB to 5.8 dB.