We demonstrated a phase-sensitive method for studying the Raman-enhanced no
ndegenerate four-wave mixing (RENFWM). The reference beam is another four-w
ave mixing signal, which propagates along the same optical path as the RENF
WM signal. This method is used for studying the phase dispersion of the thi
rd-order susceptibility X-(3) and for the optical heterodyne detection of t
he RENFWM signal.