Flat-gain wide-band erbium doped fiber amplifier by combining two difference doped fibersB. A. Hamida, S. M. Azooz, A. A. Jasim, T. Eltaif, H. Ahmad, S. Khan and S. W. HarunJ. Eur. Opt. Soc.-Rapid Publ., 10 (2015) 15015DOI: https://doi.org/10.2971/jeos.2015.15015