A novel C + L band hybrid erbium-doped fibre amplifier (EDFA) using a two-stage configuration was proposed and demonstrated experimentally. The amplifier is composed of a 0.5-m long hafnium bismuth erbium co-doped fibre (EDF) to provide gain within the C-band and a 4-m long zirconia-based EDF to provide gain within the L-band. The proposed amplifier was examined based on the multi-wavelength input source. A parallel pumping distribution technique was used to mitigate the amplifier complexity. The C + L band amplifier achieved a gain flattening of over 55 nm bandwidth for the three levels of the input powers. A gain-flattening of roughly 10.9, 15.5, and 19.2 dB were obtained, respectively, for the input signal powers of −5, −10, and −15 dBm. An average noise figure of 6.4, 5.4, and 4.7 dB was achieved, respectively, for the input signal powers of −5, −10, and −15 dBm.

Chapter 2 discusses the optical amplification properties of hafnia–bismuth erbium co-doped fiber as an active medium. The proposed amplifier is investigated by utilizing two short lengths of HBEDF to fulfill amplification in the C and L telecommunication bands where the wideband HB-EDFA is achieved using two stages in both series and parallel structures in conjunction with a double-pass scheme. Using such a novel glass composition based optical fiber, both parallel and backward pumping series HB-EDFAs show wideband operation between 1520 nm to 1610 nm.