Using high-order nonlinear Schrodinger equations including quintic nonlinearity terms

the interaction was numerically studied between the femtosecond solitons in optical fiber with positive quintic nonlinearity and compared with that of negative quintic nonlinearity.The results show that the interactions under the two nonlinearity modes are different.Under the positive quintic nonlinear effect

two neighboring femtosecond solitons attract each other and then strongly repel after combined into one.Simultaneously

the peak energy of the former soliton increases because the latter soliton transfers its partial energy to the former one.The positive quintic nonlinear effect results in the serious nonlinear drift in the central position of the femtosecond solitons. The interactions between femtosecond solitons can be restrained by the unequal phase method to some extent.