  We theoretically investigate a N-type 87Rb atomic system for efficient
generation and control of a non-degenerate Four wave mixing (FWM) signal in
pulsed regime. The susceptibility of the atomic medium is customized as a gain
profile by a weak probe field and two strong control fields which allow us to
generate the pulsed FWM signal. We study the propagation dynamics of the
generated FWM signal inside the nonlinear medium. The FWM signal obtains the
exact shape of probe pulse and travels without changing the shape whereas the
probe pulse is absorbed inside the nonlinear medium. The conversion efficiency
of this scheme without a MW field is 5.8% which can be enhanced further by
changing the control field intensity and optical depth. However, a MW field
that couples two metastable ground states enhances the conversion efficiency
three times (15.55%). The generation and control of such FWM signal in pulsed
regime has important applications in signal processing, optical communication
and quantum information science.
