Active reset of a radiative cascade for entangled-photon generation beyond the continuous-driving limit

The emission rate of entangled photons from cascaded few-level systems is limited by the dynamics of the radiative transitions. Here, we overcome the continuous driving limit for a semiconductor quantum dot via an active reset of the radiative cascade. We show theoretically and experimentally the driving regime to enable the generation of entangled photon pairs with higher fidelity and emission rate than the optimum continuously driven state. Finally, we electrically generate entangled photon pairs with an average fidelity of (79.5±1.1)% at a record clock rate of 1.15 GHz.