Compact and flat-gain fiber optical amplifier with Hafnia-Bismuth-Erbium co-doped fiber

For the first time, we demonstrated a compact Erbium-doped fiber amplifier (EDFA) using a newly developed Hafnia Bismuth Erbium co-doped fiber (HBEDF) as a gain medium. The HBEDF was fabricated using a modified chemical vapor deposition process in conjunction with solution doping technique. The fiber has high doping levels of Erbium ion of 12,500 wt ppm through incorporation of Hafnium and Bismuth ions, which prevents the clustering effect. At the input signal power of -10 dBm, a flat gain of 10.9 dB is obtained from the wavelength region of 1525 to 1565 nm with a gain variation of less than +/- 0.5 dB. The noise figure is maintained below 4.4 dB at the flat-gain region. The proposed amplifier has the potential applications in dense wavelength division multiplexing communication system due to its simplicity and compact design.