Vector pulses of self-induced transparency

A theory of an optical vector soliton of self-induced transparency (SIT) is constructed. By using the perturbative reduction method the equations of SIT for the small area pulse are reduced to the two-component coupled nonlinear Schrödinger equations. The shape of optical double periodic vector soliton with the sum and difference of the frequencies is presented. Explicit analytic expressions for the parameters of the 0π0π vector pulse of SIT are obtained. It is shown that the vector soliton in this special case can be reduced to the double breather solution of SIT and these nonlinear waves present different profiles.