Reduction of temperature-dependent multichannel gain distortion using a hybrid erbium-doped fiber cascade

Temperature dependent distortion of multichannel gain in the erbium-doped fiber amplifier (EDFA), which is a potential limiting factor in real environment, was successfully compensated by concatenating EDF's of different temperature dependence. A sample case was analyzed through a numerical simulation, for the verification of the suggested idea. Results show that temperature-dependent multichannel gain flatness distortion, except for gain level shifting, can be reduced to 0.5 dB maximum for temperature variation of 25°, which is a significant improvement over the case of Al-codoped silica fiber alone (maximum 1.8 dB for 25° variation), or ZBLAN fiber alone (maximum 1.5 dB for 25° variation).