光纤中受激Brillouin散射动态弛豫振荡特性及其抑制方法

Dynamics of relaxation oscillation caused by stimulated Brillouin scattering in optical fiber and its suppression

为了避免在高功率光纤放大器和光纤相位共轭镜等实际应用中因受激Brillouin散射(SBS)造成的光纤损伤,根据描述SBS动态弛豫振荡特性的振幅耦合方程,利用有限差分的数值模拟方法研究了光纤中SBS的动态弛豫振荡特性,并对其抑制进行了初步探讨.得到了光纤中SBS弛豫振荡在不同的脉冲上升时间的时空三维图;同时利用方波和脉冲光作抽运光进行了相应实验研究,实验结果与理论模拟结果符合很好.结果表明,增大抽运光脉冲上升时间可以有效抑制因SBS而产生的弛豫振荡,进而避免因其造成的光纤损伤.

In order to further study the dynamics of relaxation oscillation during stimulated Brillouin scattering（SBS） and to avoid optical damage caused by SBS under high power lasers in applications such as fiber amplifier and fiber phase conjugate mirror,etc.,the dynamics of relaxation oscillation during SBS in fibers are studied on the basis of the SBS coupled amplitude equations using numerical simulations of finite difference methods. Meanwhile,we propose a method to suppress the relaxation oscillation. For different rise time of SBS pump pulse,the temporal and spatial variation of intensities of pump and Stokes waves is plotted as three-dimensional figures. The corresponding experiments have been conducted and the experimental results agree well with the theoretical results. From the experiments and numerical calculations it can be concluded that,by increasing the rise time of SBS pump pulse the relaxation oscillation can be suppressed effectively and the optical damage caused by SBS can be avoided consequently.