拉曼效应和参量放大共同作用下增益谱特性

The gain spectrum character under Raman scattering and parametric amplification

根据激光脉冲在双折射光纤中传输时,拉曼效应和参量放大共同作用下所所遵循的耦合模方程,基于平行拉曼增益的洛伦兹模型,给出了输入抽运波偏振方向沿相互正交的双折射轴时,拉曼效应和参量放大共同作用所导致的增益.讨论并分析了在不同色散区相关参量对增益谱特性的影响.结果表明,拉曼效应改变了非线性和色散的相互平衡,使得参量放大斯托克斯波与反斯托克斯波增益谱彼此不对称;当输入功率一定时,其增益谱结构确定,非线性系数和色散系数两者之间相对变化时,增益谱的强度和展宽有所改变.

According to the nonlinear coupled equation under the joint action of Raman scattering and parametric amplification when the optical pulse propagats in the birefringent fiber, based on Lorentzian model of parallel Raman gain spectrum, the gain spectrum is obtained by combining Raman scattering and parametric amplification when the pump wave polarization direction is along the two orthogonal birefringence axes. The gain spectrum is discussed as a function of input parameters （input power, the group velocity mismatch） in different dispersion regimes. The result shows that the balance between non-linearity and dispersion is destructed by Raman scattering. Stokes and anti-stokes gain spectrum are asymmetric because of Raman effect. The structure of gain spectrum is confirmed when input power is constant. The intensity and width of gain spectrum change with dispersion and nonlinear parameter.