Study of heavily thulium-doped fiber amplifier for optical telecom at 2μm

In this study, the performance of a thulium-doped fiber amplifier is investigated for optical telecom at 2 mu m with the pump wavelength of 1570nm. The influence of energy up-conversion transitions has been built up on the theoretical model. A heavily thulium doped concentration has been chosen in order to consider this ion-ion interaction. The rate and propagation equations have been developed to study and evaluate the characteristics of a thulium doped fiber amplifier with considering the effects of amplified spontaneous emission noise, cross relaxation process and energy up-conversion. A MATLAB program has been developed to optimise the fiber length and compute the amplifier gain and noise figure. Through the numerical results it is indicated that a short thulium fiber length is require which is a one attractive advantage to choose a thulium fiber with high concentration. However, the results also showed that increasing of thulium doping concentration reduces the signal gain when pumped at 1570nm.