  We analyze the superconducting state and c-axis charge dynamics of cuprates
at optimal doping using a charge ordered bilayer superlattice model in which
pairing is supported by inter-layer Coulomb energy gain (potential energy
driven superconductivity).The 2D pair-condensate can be characterized by a
charge ordered state with a "checkerboard" like pattern seen by scanning
tunneling microscopy.The pair condensation might lead to the sharp decrease of
the normal state c-axis anisotropy of the hole content and hence to the
decrease of inter-layer dielectric screening.The decrease of the c-axis
dielectric screening can be the primary source of the condensation energy below
$T_c$. We find that a net gain in the electrostatic energy occurs along the
c-axis, which is proportional to the measured condensation energy ($U_0$) and
with $T_c$:$E_c^{3D} \approx 2 (\xi_{ab}/a_0+1)^2 U_0 \approx k_B T_c$ and is
due to inter-layer charge complementarity (charge asymmetry of the boson
condensate) where $\xi_{ab}$ is the coherence length of the condensate and $a_0
\approx 3.9 \AA$ is the in-planelattice constant.
