High-rate entanglement source via two-photon emission from semiconductor quantum wells

We propose a compact high-intensity room-temperature source of entangled photons based on the efficient second-order process of two-photon spontaneous emission from electrically pumped semiconductor quantum wells in a photonic microcavity. Two-photon emission rate in room-temperature semiconductor devices is determined solely by the carrier density, regardless of the residual one-photon emission. The microcavity selects two-photon emission for a specific signal and idler wavelengths and at a preferred direction without modifying the overall rate. Pair-generation rate in GaAs∕AlGaAs quantum well structure is estimated using a 14-band model to be 3 orders of magnitude higher than for traditional broadband parametric down-conversion sources.