2022/07/22 by Saverio Francesconi, Francesconi, S., A. Raymond +13 · 5 citations
Computer Science · Engineering · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Neural Networks and Reservoir Computing #Optics (physics.optics) #Photonic and Optical Devices #Quantum Information and Cryptography #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2207.10943
openalex publication_date 2022/07/22 · openalex created_date 2022/07/27 · openalex updated_date 2026/08/03
We demonstrate a chip-integrated semiconductor source that combines polarization and frequency entanglement, allowing the generation of entangled biphoton states in a hybrid degree of freedom without postmanipulation. Our AlGaAs device is based on type-II spontaneous parametric down-conversion (SPDC) in a counterpropagating phase-matching scheme, in which the modal birefringence lifts the degeneracy between the two possible nonlinear interactions. This allows the direct generation of polarization-frequency entangled photons, at room temperature and telecom wavelength, and in two distinct spatial modes, offering enhanced flexibility for quantum information protocols. The state entanglement is quantified by a combined measurement of the joint spectrum and Hong-ou-Mandel interference of the biphotons, allowing to reconstruct a restricted density matrix in the hybrid polarization-frequency space.