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Photonic quantum information processing and communication demand highly integrated device platforms, which can offer high-fidelity control of quantum states and seamless interface with fiber-optic networks simultaneously. Exploiting the unique quantum emitter characteristics compatible with photonic transduction, combined with the outstanding nonlinear optical properties of silicon carbide (SiC), we propose and numerically investigate a single-crystal cubic SiC-on-insulator (3C-SiCOI) platform toward multi-functional integrated quantum photonic circuit. Benchmarking with the state-of-the-art demonstrations on individual components, we have systematically engineered and optimized device specifications and functions, including state control via cavity quantum electrodynamics and frequency conversion between quantum emission and telecommunication wavelengths, while also considering the manufacturing aspects. This work will provide concrete guidelines and quantitative design considerations for realizing future SiCOI integrated photonic circuitry toward quantum information applications. 

Spin defects in silicon carbide have the advantage of exceptional electron spin coherence combined with a near-infrared spin-photon interface, all in a material amenable to modern semiconductor fabrication. Leveraging these advantages, we integrated highly coherent single neutral divacancy spins in commercially available p-i-n structures and fabricated diodes to modulate the local electrical environment of the defects. These devices enable deterministic charge-state control and broad Stark-shift tuning exceeding 850 gigahertz. We show that charge depletion results in a narrowing of the optical linewidths by more than 50-fold, approaching the lifetime limit. These results demonstrate a method for mitigating the ubiquitous problem of spectral diffusion in solid-state emitters by engineering the electrical environment while using classical semiconductor devices to control scalable, spin-based quantum systems. 

Interfacing solid-state defect electron spins to other quantum systems is an ongoing challenge. The ground-state spin’s weak coupling to its environment not only bestows excellent coherence properties but also limits desired drive fields. The excited-state orbitals of these electrons, however, can exhibit stronger coupling to phononic and electric fields. Here, we demonstrate electrically driven coherent quantum interference in the optical transition of single, basally oriented divacancies in commercially available 4H silicon carbide. By applying microwave frequency electric fields, we coherently drive the divacancy’s excited-state orbitals and induce Landau-Zener-Stückelberg interference fringes in the resonant optical absorption spectrum. In addition, we find remarkably coherent optical and spin subsystems enabled by the basal divacancy’s symmetry. These properties establish divacancies as strong candidates for quantum communication and hybrid system applications, where simultaneous control over optical and spin degrees of freedom is paramount.