Rigorous modeling of stimulated Brillouin scattering-induced rogue waves in a high-power fiber amplifier

Stimulated Brillouin scattering (SBS) is considered to be a huge limiting factor in the power scaling of a narrow-linewidth high-power fiber amplifier source. An in-depth comprehensive study on this matter is of great importance because the generation of a temporarily strong rogue wave (RW) in the gain fiber can give rise to catastrophic damage to the key components of the fiber amplifier source. Since the center frequency of SBS is sensitive to temperature, in this paper, we extensively model and investigate its spatio-temporal behaviors by constructing a set of generalized coupled equations between the optical and acoustic waves together with the transient analysis of the corresponding thermal effect along the fiber length, depending on two different strategies in terms of the way of the pump power increase. When the pump power was turned on slowly in a multi-step manner, it could diminish the peak power level of SBS-induced RWs by a factor of almost two relative to that of SBS-induced RWs formed when the pump power was turned on immediately in a single-step manner. The outcome of this study will be useful and helpful in analyzing and designing narrow-linewidth high-power fiber amplifier as well as investigating their thermal management.