Phys.org December 28, 2022
There has been exciting recent progress in satellite-based quantum communications and quantum repeaters, but a lack of suitable single-photon sources has hampered further advances. The visibility of quantum interference between independent QDs rarely went beyond the classical limit of 50%, and the distances were limited from a few meters to kilometers. An international team of researchers (China, Germany) has shown quantum interference between two single photons from independent QDs separated by a 302 km optical fiber. The single photons were generated from resonantly driven single QDs deterministically coupled to microcavities. Quantum frequency conversions were used to eliminate the QD inhomogeneity and shift the emission wavelength to the telecommunication band. The observed interference visibility was 0.67 ± 0.02 (0.93 ± 0.04). According to the researchers’ improvements can further extend the distance to ∼600 km. Their work represents a key step to long-distance solid-state quantum networks…read more. Open Access TECHNICAL ARTICLE
Experimental configuration of quantum interference between two independent solid-state QD single-photon sources… Credit: Advanced Photonics, Vol. 4, Issue 6, 066003 (December 2022)