High-power Er-Yb-doped fiber amplifier with multichannel gain flatness within 0.2 dB over 14 nm

A high-power Er-Yb fiber amplifier for WDM applications has been constructed using a matched mid-stage gain shaping filter. Using precise measurements and careful design considerations, excellent gain flatness, with less than 0.2-dB variation, was obtained over a 14-nm spectral bandwidth. By simply adjusting the pump power to the amplifier, it was possible to maintain the flattened amplifier gain shape over a wide input signal power range from -11 dBm to 1 dBm. A low external noise figure of 5.2 dB at 1-dBm signal input and a high-output power up to 24.6 dBm has been measured.