Modulation instability in optical fiber induced by cross-phase modulation

A new kind of modulation instability of continuous signal in optical fiber induced by nonlinear interaction of two copropagating optical fields is studied theoretically. It is shown by numerical simulation that the phenomenon of the recurrence to the state of continuous signal with initial amplitudes takes place after the instability growth process if the initial amplitudes of two optical fields are equal. The recurrence phenomenon is absent for unequal initial amplitudes. It is concluded that the new type of modulation instability in optical fiber permits to obtain periodical sequence of pulses from continuous pumping in the range of positive dispersion of group velocities.