Quantum Frequency Conversion of a Quantum Dot Single-Photon Source on a Nanophotonic Chip
Anshuman Singh, Qing Li, Shunfa Liu, Ying Yu, Xiyuan Lu, Christian Schneider, Sven Hofling, John R. Lawall, Varun B. Verma, Richard P. Mirin, Sae Woo Nam, Jin Liu, Kartik A. Srinivasan
Single self-assembled InAs/GaAs quantum dots are promising bright sources of indistinguishable photons for quantum information science. However, their distribution in emission wavelength, due to inhomogeneous broadening inherent to their growth, has limited the ability to create multiple identical sources. Quantum frequency conversion can overcome this issue, particularly if implemented using scalable chip-integrated technologies. Here, we report quantum frequency conversion of a quantum dot single-photon source on a silicon nanophotonic chip. Single photons from a quantum dot in a micropillar cavity are shifted in wavelength with an on-chip conversion efficiency ~ 12 %, limited by the linewidth of the quantum dot photons. The intensity autocorrelation function g(2)(t) for the frequency-converted light is antibunched with g(2)(0) = 0.290 +/- 0.030, compared to the before conversion value g(2)(0) = 0.080 +/- 0.003. We demonstrate the suitability of our frequency conversion interface as a resource for quantum dot sources by characterizing its effectiveness across a wide span of input wavelengths (> 140 nm), and its ability to achieve tunable wavelength shifts difficult to obtain by other approaches.