An erbium-doped fiber amplifier with dynamically gain-flattened spectrum

Summary form only given. Most gain-flattened erbium-doped fiber amplifiers (EDFAs) can work only at specific operation condition (except the dynamic-flattened EDFA with Mach-Zehnder (MZ) filter). MZ filter and long-period fiber grating are expensive and may be temperature sensitive. We found that we can improve the gain and noise figure (NF) by bending the initial part of erbium-doped fiber (EDF). In this paper, we bend dispersion-shifted fiber (DSF) inserted in the middle of EDF to obtain the dynamically flattened gain spectrum.