Vector combined and crossing Kuznetsov-Ma solitons in -symmetric coupled waveguides

A variable-coefficient coupled nonlinear Schrodinger equation with balanced gain and loss is studied, and two kinds of analytical Kuznetsov-Ma soliton solutions including combined Kuznetsov-Ma soliton solution and crossing two-Kuznetsov-Ma soliton solution are obtained. In a diffraction decreasing system, the control for the excitation of two kinds of Kuznetsov-Ma soliton including rear excitation, peak excitation and initial excitation is investigated. The different peak locations of Kuznetsov-Ma soliton along the propagation direction appear repeatedly, which makes rear excitation, peak excitation and initial excitation happen again and again.