Fig. 1. Diagram of an EYDFA with a pump-end Yb-band FBG. ISO, isolator; PC, pump combiner.

Fig. 2. Absorption and emission cross sections of Yb and Er ions of the gain fiber.

Fig. 3. (a) Simulated results of the output power of the amplified signal and residual power of the FBG reflection as a function of the center wavelength of the FBG. (b) Power evolutions of the pump, signal, and FBG reflection of the four marked featuring configurations.

Fig. 4. (a) Yb and (b) Er ASE spectra of EYDFAs with and without the Yb-band FBG.

Fig. 5. Output power of the EYDFA as a function of the reflectivity of the FBG.

Fig. 6. (a) Output power of the amplified signal and residual power of the FBG reflection of EYDFAs with (b) optimal gain fiber lengths as a function of the center wavelength of the FBG.