横向受激布里渊散射的抑制

Suppression of transverse stimulated Brillouin scattering

从非线性光学的耦合波理论出发,结合流体力学的连续性方程,建立了光学元件中窄带泵浦的横向受激布里渊散射的二维理论模型,并在此基础上,利用数值模拟考察泵浦光带宽增加对受激散射过程的影响。研究表明:在一定的条件下,当泵浦光带宽略大于布里渊线宽时,受激散射过程的Stokes增益将显著降低;带宽越大,Stokes增益降低得越多;当带宽大于20GHz时,可以抑制横向受激布里渊散射带来的不良影响。另外,当带宽一定时,调制频率的改变也会影响受激散射过程,可以通过数值模拟确定最佳的调制频率。

The coupled wave theory of nonlinear optics and continuous equations of hydromechanics are adopted to establish two-dimensional theoretical model of seeded and narrowband pumped transverse SBS. Based on these equations, investigations of the effect of broadband pump on Stokes gain are presented by numerical simulations. The investigation shows that the SBS gain will decrease significantly if laser bandwidth are a little greater than the SBS linewidth. Greater the bandwidth, less the Stokes gain. The bad effects induced by transverse SBS can be suppressed when the bandwidth is greater than 20GHz. On the other hand, modulation frequency will influence Stokes gain and the optimal frequency through the numerical simulations can be chosen.