S-band optical amplification technologies for EDFAs

This paper reports a new approach of applying erbium-doped fiber to an S-band optical amplifier and comparing it with a gain-shifted thulium-doped fluoride fiber amplifier. S-band erbium-doped fiber amplifiers for WDM transmission systems have achieved gains of over 25 dB in wavelengths from 1489 to 1519 nm through the use of silica-based EDFs and ASE suppressing filters. We discuss the feasibility of introducing S-band EDFAs to improve the power conversion efficiencies and gain flatness.