  We investigate propagation of a pulse pair in a three-level medium under the
adiabatic following condition for the general case of unequal oscillator
strengths. Exact analytical solutions to the propagation equations have been
obtained. It is shown that propagation dynamics strongly depends on the
relationship between oscillator strengths. The adiabaticity criterion for the
interaction of pulses with three-level media has been derived and analyzed in
detail.
