  Generation of polarization-entangled photons from quantum dots via the
biexciton-exciton recombination cascade is complicated by the presence of an
energy spitting between the intermediate excitonic levels, which severely
degrades the quality of the entangled photon source. In this paper we present a
novel, conceptually simple and straightforward proposal for restoring the
entanglement of said source by applying a cascade of time-dependent operations
on the emitted photons. This is in striking contrast with the techniques
usually employed, that act on the quantum emitter itself in order to remove the
fine structure splitting at its root. The feasibility of the implementation
with current technology is discussed, and the robustness of the proposed
compensation scheme with respect to imperfections of the experimental apparatus
is evaluated via a series of Monte Carlo simulations.
