  We theoretically study the optomechanically induced transparency (OMIT) and
absorption(OMIA) phenomena in a single microcavity optomechanical system,
assisted by an indirectly-coupledauxiliary cavity mode. We show that the
interference effect between the two optical modes playsan important role and
can be used to control the multiple-pathway induced destructive or
construc-tive interference effect. The three-pathway interference could induce
an absorption dip within thetransparent window in the red sideband driving
regime, while we can switch back and forth betweenOMIT and OMIA with the
four-pathway interference. The conversion between the transparencypeak and
absorption dip can be achieved by tuning the relative amplitude and phase of
the multiplelight paths interference. Our system proposes a new platform to
realize multiple pathways inducedtransparency and absorption in a single
microcavity and a feasible way for realizing all-opticalinformation processing.
