Ultrabroadband Entangled Photons on a Nanophotonic Chip

The development of quantum technologies on nanophotonic platforms has seen momentous progress in the past decade. Despite that, a demonstration of time-frequency entanglement over a broad spectral width is still lacking. Here we present an efficient source of ultrabroadband entangled photon pairs on a periodically poled lithium niobate nanophotonic waveguide. Employing dispersion engineering, we demonstrate a record-high 100 THz (1.2 mu m-2 mu m) generation bandwidth with a high efficiency of 13 GHz/mW and excellent noise performance with the coincidence-to-accidental ratio exceeding 10(5). We also measure strong time-frequency entanglement with over 98% two-photon interference visibility.

Automated summary

Development of quantum technologies on nanophotonic platforms has made significant progress in the past decade, but a demonstration of time-frequency entanglement over a broad spectral width is still lacking.