DEPENDENCE OF THE GAIN IN HfBi-EDFA ON THE PUMPING CONFIGURATION AND ACTIVE FIBER LENGTH

In this study, gain dependence in Hafnium-Bismuth-Erbium co-doped fiber amplifier (HfBi- EDFA) on pumping configuration and active fiber length were analyzed experimentally. Gain and signal output power characteristics of the heavily co-doped HfBi-EDFA pumped with a 980 nm pump laser were experimentally obtained for different pumping methods (forward, backward and bidirectional) as functions of pump power, signal input power, and wavelength. During the study, 0.3 m and 1.1 m long HfBi-EDF and a signal input power of -30 dBm at 1550 nm were used, and the pump power was increased from 60 mW to 204 mW. A moderate gain of over 11 dB was obtained in forward and backward pumping configurations but the gain has remained at around 7 dB in the bidirectional pumping configuration. The spectral gain measurements were realized across a 1520 nm - 1605 nm wavelength range, and the forward and backward pumping configurations resulted in the best gain values at 1532 nm with a gain of around 17 dB. It was also shown that when the HfBi-EDF length is 0.3 m, optical amplification in the C band is achieved. For the fiber length of 1.1 m, the gain spectrum shifts towards the L band.