零色散附近的交叉相位调制不稳定性分析

以三、四阶色散项的耦合非线性薛定谔方程为基础，考虑光纤损耗及高阶色散，研究了双光束在零色散附近的交叉相位调制不稳定性.理论上导出描述交叉相位调制不稳定性的色散方程，并进行数值模拟计算.结果表明：由于四阶色散的影响，在光纤的正常、反常色散区，交叉相位调制不稳定性均发生在两个频谱区.如光脉冲工作在最小群速度色散附近时，四阶色散对光纤的交叉相位调制不稳定性将起决定性作用，可使增益谱出现一个新的峰值.光纤损耗使增益的谱宽变窄.对给定的传输距离，随着光纤向零色散附近靠近，两个频谱区谱宽增加直到相互重叠.数值分析了两光波有差别时的交叉相位调制不稳定性.

Cross-Phase Modulational Instability in the Region of Minimum Group-velocity Dispersion

Cross-phase modulational instability created by two beams of lights in the region of minimum group-velocity dispersion is investiga ted based on extended nonlinear Schrdinger equation with the fiber loss and high -order dispersion considered.The dispersion equation which describes the cross -phase modulational instability is obtained,and the numerical simulation is don e.It is shown that because of the fourth-order dispersion,cross-phase modulati onal instability occurs at two spectrum regions in both anomalous and normal dis persion regimes of fiber. When second-order dispersion approaches the minimum v alue at the so-called zero dispersion wavelength,fourth-order dispersion domin ates the cross-phase modulational instability and makes a new crest in the gain spectrum.Research also shows that fiber loss reduces the frequency range of the gain spectrum.For a given dispreading distance,the widths of the two spectrum r egions increase until overlay when second-order dispersion approaches zero.When two beams of lights have difference,the cross-phase modulational instability i s analyzed numerically.