  In the present paper, we consider nonlinear PT-symmetric dimers and trimers
(more generally, oligomers) embedded within a linear Schr{\"o}dinger lattice.
We examine the stationary states of such chains in the form of plane waves, and
analytically compute their reflection and transmission coefficients through the
nonlinear PT symmetric oligomer, as well as the corresponding rectification
factors which clearly illustrate the asymmetry between left and right
propagation in such systems. We examine not only the existence but also the
dynamical stability of the plane wave states and interestingly find them to be
generically unstable. Lastly, we generalize our numerical considerations to the
more physically relevant case of Gaussian initial wavepackets and confirm that
the asymmetry in the transmission properties persists in the case of such
wavepackets, as well.
