  This work is devoted to the research of conditions of the dark resonance
(coherent population trapping) of the interaction of the laser radiation with
tunneling-coupled quantum wells. The phase sensitive dependence of dark
resonances has been investigated. We obtained that destruction as well as
restoration of the dark resonances of the coherent population trapping is
possible in dependence on algebraic sum of the phases of exciting fields. It is
shown that the phase variation of exciting fields influences on the absorption
and dispersion of the probe field in a medium with quantum wells.
