光子晶体光纤中基于SBS实现慢光的数值模拟

Numerical simulation of SBS-based formation of slow light in photonic crystal fibers

通过运用四阶龙格库塔法和特征线法对基于光子晶体光纤的受激布里渊散射耦合方程组进行数值求解,讨论不同纤芯直径的光子晶体光纤在相同的Stokes波功率和相同的Stokes波强度下对受激布里渊散射慢光产生的影响,发现芯径越小PCF的时延特性越好,但是伴随着较大的脉冲展宽,对于Stokes波脉冲,较小的输入Stokes波功率具有更大的时延.考察不同的脉冲宽度对光子晶体光纤中的慢光的影响,发现较短的脉冲具有更大的相对时延并伴随着较大的脉冲展宽.通过改变小芯径光子晶体光纤的占空比,讨论光子晶体光纤的结构变化对受激布里渊散射慢光的影响,发现小芯径PCF的占空比越小,对应的SBS慢光的时延越大,脉冲展宽也越明显.以上结论可以为慢光缓存器的设计提供理论参考.

The photonic crystal fibers （PCF）-based stimulated Brillouin scattering（SBS） coupled equa- tions were solved by using fourth-order Runge-Kutta method and characteristics method. The influence of fiber-core diameter on SBS slow light was discussed in condition of constant Stokes power and Stokes wave pulse intensity. It was found that the smaller the fiber core was the better the PCF time delay would be, but with larger pulse broadening, a smaller input of Stokes wave power would result in a larger time delay of Stokes wave pulse. The influence of different pulse width on the slow light in PCF was investigated and it was found that smaller pulse would result in a larger relative time delay with a larger pulse broadening. By means of changing the duty ratio of PCF with small core diameter, the influence of structural variation of PCF on SBS slow light was discussed and it was found that the less the duty ratio of PCF with small core was the more the time delay of SBS slow light would be and the more remarkable the pulse broadening would be. The foregoing conclusion could provide a theoretical basis for designing the buffer of the slow light.