Propagation Loss and Non-linear effects on Modulation Instability in Thulium Doped Fiber Amplifiers operating in S and near-C bands

This paper presents the loss factor effect on the behaviour of Modulation Instability (MI) in Thulium Doped Fiber Amplifier (TDFA) operational in $\mathbf{S}$ and near-C bands. Based on the derived analytical model, the relative change in maximum signal gain with respect to perturbation frequency was observed and compared to lossless TDFAs. At a smallsignal attenuation coefficient of 0.01 /m corresponding to smallsignal attenuation of 0.36 frequency shift of 1.44 THz was observed. Consequently, a reduction in signal gain of 45 dB was obtained for an input signal power of 250 mW. For the same set of parameters, the effect of non-linear and loss factor was studied and compared with present-day state-of-the-art Erbium Doped Fiber Amplifiers (EDFA). The results obtained can be used constructively in the selection of optimum perturbation frequency under MI phenomenon for the design of MI-based lasers employing TDFAs.