Nonlinear Photonics in Silicon Carbide Systems

Silicon carbide (SiC) offers a unique combination of wide bandgap, high refractive index and strong second- and third-order nonlinearities, making it an exceptional platform for integrated photonics. Advances in materials processing have enabled the fabrication of high‐quality waveguides, microring resonators and hybrid bonded structures in various SiC polytypes and amorphous films. Dispersion engineering in these devices supports efficient frequency conversion processes—from second-harmonic and difference‐frequency generation to Kerr microcomb and soliton formation—at low power thresholds. The intrinsic robustness, thermal conductivity and chemical inertness of SiC, together with its compatibility with complementary metal-oxide-semiconductor (CMOS) fabrication, underpin applications in optical communications, sensing, metrology and emerging quantum information technologies. Recent progress in electro-optic modulation, spontaneous parametric down‐conversion and entangled photon-pair sources further highlights the global significance of nonlinear photonics in SiC.

Research from Nature Portfolio

Recent studies have demonstrated on-chip nonlinear and quantum light sources in cubic SiC on insulator, where microring geometries yield high second-harmonic generation efficiencies and broadband difference-frequency conversion. Spontaneous parametric down-conversion in these devices produces photon pairs with high generation rates and low noise, while time-bin entanglement with visibilities exceeding 85 % has been observed, signalling strong potential for integrated quantum circuits. Complementing these findings, the first waveguide-integrated Pockels modulator in SiC has been realised, operating at gigahertz bandwidth under CMOS-level voltages. This device exhibits stable performance at high optical intensities without photorefractive effects, paving the way for monolithic electro-optic control within robust SiC platforms.

Nonlinear Photonics in Silicon Carbide Systems publication trend

The graph below shows the total number of articles in nonlinear photonics in silicon carbide systems across all publications each year (not limited to Nature Index journals).

Technical terms

Second-order nonlinearity (χ(2)): Optical response enabling frequency doubling and mixing.

Third-order nonlinearity (χ(3)): Optical response responsible for Kerr effect and four-wave mixing.

Dispersion engineering: Tailoring of group-velocity dispersion to phase-match nonlinear interactions.

Quality factor (Q): Ratio of stored energy to energy loss per optical cycle in a resonator.

Microring resonator: Circular waveguide structure supporting high-Q resonances.

Optical parametric oscillation: Coherent light generation via χ(3) processes in a resonator.

Pockels effect: Linear electro-optic modulation arising from χ(2) in non-centrosymmetric crystals.

References

1. Inverse-designed silicon carbide quantum and nonlinear photonics. Light: Science & Applications (2023).
2. High-Quality Amorphous Silicon Carbide for Hybrid Photonic Integration Deposited at a Low Temperature. ACS Photonics (2023).
3. Silicon‐On‐Silicon Carbide Platform for Integrated Photonics. Advanced Optical Materials (2024).
4. An integrated 3C-silicon carbide-on-insulator photonic platform for nonlinear and quantum light sources. Communications Physics (2024).
5. Integrated silicon carbide electro-optic modulator. Nature Communications (2022).
6. Soliton formation and spectral translation into visible on CMOS-compatible 4H-silicon-carbide-on-insulator platform. Light: Science & Applications (2022).