An integrated 3C-silicon carbide-on-insulator photonic platform for nonlinear and quantum light sources

Abstract Silicon carbide (SiC) polytypes are emerging for integrated nonlinear and quantum photonics due to their wide-bandgap energies, second-order optic nonlinearity and process compatibility with complementary metal-oxide-semiconductor technologies. Among polytypes, 3C-SiC is the only one epitaxially grown on wafer-scale silicon substrates. However, on-chip nonlinear and quantum light sources leveraging the second-order nonlinearity of 3C-SiC have not been reported to our knowledge. Here, we design and fabricate an elliptical microring on 3C-SiC. We demonstrate a nonlinear light source with a second-harmonic generation efficiency of 17. 4 0. 2 \% W^-1 17. 4 ± 0. 2 % W − 1 and difference-frequency generation with a signal-idler bandwidth of 97 nm. We demonstrate a spontaneous parametric down-conversion source with a photon-pair generation rate of 4. 8 MHz and a coincidence-to-accidental ratio of 3361 84 3361 ± 84. We measure a low heralded single-photon second-order coherence g₇^ (2) =0. 0007 g H 2 = 0. 0007. We observe time-bin entanglement with a visibility of 86. 0 2. 4 \% 86. 0 ± 2. 4 % using this source. Our work paves a way toward SiC-based on-chip nonlinear and quantum photonic circuits.