光子晶体光纤结构与掺杂对受激布里渊散射快光的影响

由受激布里渊散射三波耦合方程导出了在小信号条件下的快光时间提前量，通过全矢量有限元法模拟了光子晶体光纤占空比和GeO₂掺杂质量分数对布里渊频移、时间提前量、脉冲展宽因子及脉冲形变的影响。结果表明，布里渊频移随着占空比和掺杂质量分数的增大而减小。在保持泵浦功率为20 mW和快光传输长度为10 m的条件下，时间提前量随着占空比的增大而增大，随着掺杂质量分数的增大而减小。脉冲展宽因子与时间提前量变化趋势相反。当占空比为0.8，Ge掺杂质量分数为18%时，能够实现快光时间提前量为29.7 ns，脉冲展宽因子为0.88。布里渊阈值随着占空比的增大而减小，随着掺杂质量分数的增大而增大。

Influence of Structure and Doping on Stimulated Brillouin Scattering Fast Light in Photonic Crystal Fibers

Time advancement of fast light in small signal regime was derived from three wave coupling equations of stimulated Brillouin scattering(SBS) in photonic crystal fibers(PCFs), and the influence of air-filling ratio and doping(doped GeO₂) on Brillouin frequency shift, time advancement, pulse broadening factor and pulse deformation were simulated by full vectorial finite element method. The results show that the Brillouin frequency shift decreases with the increase of air-filling ratio and doping mass fraction. The time advancement increases with the increase of air filling factor, but decreases with the increase of doping mass fraction at a given pump power of 20 mW and fiber length of 10 m. The varying trend of broadening factor is just contrary to that of the time advancement. The time advancement of 29.7 ns and the pulse broadening factor of 0.88 are achieved at the air filling factor of 0.8 and GeO₂ doping mass fraction of 18%. The Brillouin threshold decreases with the increment of filling factor and decrement of doping mass fraction.