光子晶体光纤中的参变放大与拉曼散射

Parametric Amplification and Raman Scattering in Photonic Crystal Fiber

光子晶体光纤(PFC)有着传统光纤无法比拟的优良特性,特别是具有极好的非线性效应和双折射效应;当输入抽运波偏振方向同双折射轴成45°时,通过引入拉曼增益的洛伦兹模型,研究了光子晶体光纤中在参变放大和拉曼散射共同作用下的增益谱特性。结果表明,由于参变放大和拉曼散射的相互作用,输入功率和群速度失配对光子晶体光纤的增益有重要影响。随着输入功率和群速度失配的增大,增益谱强度增强,宽度加宽。在反常色散区,输入功率较大并达到稳定时,斯托克斯波增益谱呈现多峰结构;在正常色散区,斯托克斯波增益大于反斯托克斯增益。当满足一定关系时,在光子晶体光纤中传播的抽运波可以分解为脉冲序列,由此分离和提取T频脉冲。

Photonic crystal fiber （PCF） has excellent features compared with the traditional optical fiber, especially nonlinear effect and birefringence effect. By quoting Lorentzian model of Raman gain spectra in PCF, the gain spectra are studied under the action of Raman scattering together with parametric amplification, when the pump wave polarization is oriented at 45~ between the axes. The result shows that the input power and the group velocity mismatching have a great influence on the gain spectra because of the interaction between parametric amplification and Raman scattering. The gain spectrum bandwidth widened and the intensity enhanced as the input power and the group-velocity mismatching enlarged. Stokes-wave is multiple-peaked structure when input power is greater and stable in anomalous dispersion regime . The Stokes-waves gain are greater than anti-Stokes waves gain in normal dispersion regime. The pump wave can be changed into pulse array under certain conditions so that the T-frequency pluses can be extracted from it.