Polarization and Spatial Mode Dependent Four-wave Mixing in a 4H-Silicon Carbide Microring Resonator

We report four-wave mixing with different polarization and spatial modes in a single 4H-silicon carbide photonic device. Our device shows great potential to perform high-dimensional multiplexing for optical communication and highdimensional entanglement in quantum networks. We use a polarization insensitive grating coupler and a multimode microring resonator that supports three polarization and spatial mode resonances. Finally, we show the polarization dependence of the third-order nonlinearity of 4H-silicon carbide. The measured nonlinear refractive index of the light polarized along the extraordinary axis, which is n₂,_TM=(13.1±0.7)×10⁻¹⁹m²/W, is twice as large as that of the light polarized along the ordinary plane, n_2,TE=(7.0 ± 0.3)×10⁻¹⁹ m²/W, indicating that the extraordinary polarization is more efficient for nonlinear experiments in the 4H-silicon carbide integrated platforms as compared to the ordinary polarization.