  Coulomb interactions between confined carriers remove degeneracies in the
excitation spectra of quantum dots. This provides a which path information in
the cascade decay of biexcitons, thus spoiling the energy-polarization
entanglement of the emitted photon pairs. We theoretically analyze a strategy
of color coincidence across generation (AG), recently proposed as an
alternative to the previous, within generation (WG) approach. We simulate the
system dynamics and compute the correlation functions within the density-matrix
formalism. This allows to estimate quantities that are accessible by a
polarization-tomography experiment, and that enter the expression of the
two-photon concurrence. We identify the optimum parameters within the AG
approach, and the corresponding maximum values of the concurrence.
