Wide-bandgap waveguide platform with quantum + high-power + mid-IR potential
Physics / mechanism
4H-silicon-carbide (4H-SiC) has a wide bandgap (~3.2 eV) making it transparent from UV through near-IR with low absorption. Refractive index ~2.6 at 1550 nm gives reasonable mode confinement. Critically, SiC hosts color centres — silicon vacancies (V_Si), divacancies, and nitrogen-vacancy-like defects — that emit single photons at telecom wavelengths and can store quantum information for milliseconds at room temperature. SiC also has thermal conductivity ~490 W/m·K (vs silicon’s 150 W/m·K), enabling high-power photonic ICs that silicon can’t host without thermal failure.
The materials-processing path is unique among emerging photonic platforms: SiC has a mature CMOS-style fab ecosystem from power electronics (Wolfspeed, ST, onsemi, Infineon), but those fabs run different epi/etch recipes than would be needed for low-loss photonic waveguides. The repurposing question is real and unresolved.
Competitive landscape
Lab demonstrators only as of 2026. Commercial production: zero foundries. Active research: Marko Lončar group (Harvard), HRL Labs (US), Princeton (Englund/Awschalom-derived programmes), Linköping University (Sweden, the SiC PIC pioneer). Best-demonstrated waveguide loss ~1–2 dB/cm for 4H-SiC-on-insulator; the trajectory is comparable to where TFLN was in 2018–2019.
Closest peers:
- Diamond for quantum (NV centres) — even better quantum coherence but worse manufacturing path
- Silicon Nitride for low-loss visible — much more mature but no native quantum emitters
- Gallium Nitride for wide-bandgap photonics — different application focus
Frontier (open questions)
See frontmatter frontier: block.