Research Progress in Quantum and Nonlinear Integrated Photonics on 4H-SiCOI +
The band gap of 4H-SiC is about 3.2eV, and its transparent window covers a wide range of wavelengths from ultraviolet (about 387 nm) to mid infrared (5.6μm). In addition, 4H-SiC has a non centrosymmetric crystal structure (point group 6mm) and significant second-order nonlinear optical coefficients (such as χ1552 ≈-23.4 pm/V), which can be used to achieve nonlinear processes such as spontaneous parametric down conversion (SPDC) and second harmonic generation (SHG). In recent years, with the maturity of wafer level 4H-SiCOI preparation technology, this platform has become a highly competitive candidate material in integrated photonics. PAM-XIAMEN can offer 4H-SiCOI thin films, detailed structure please consult: [email protected]
1. Preparation of 4H–SiCOI
Traditional SiC bulk crystal processing or heteroepitaxy methods often face lattice misalignment and interface state challenges, which limit their integrated applications. Recently, Yi et al. used innovative ion cutting and layer transfer techniques to bond single crystal 4H-SiC thin films onto silicon oxide substrates, achieving the preparation of 4H-SiCOI structures. This process includes steps such as hydrogen ion implantation, room temperature bonding, high-temperature annealing, and chemical mechanical polishing (CMP). The SiC film prepared by this process exhibits excellent uniformity, with an average thickness of 1102.2nm, a standard deviation of only 2.2nm, and a surface roughness of less than 0.5nm. X-ray diffraction (XRD) testing shows that the (0004) peak full width at half maximum (FWHM) of the annealed 4H-SiC film is 75.6 arcsec, close to the bulk material level, indicating its good crystal quality.
Fig. 1 Untreated and processed 4H-SiC images (a) XRD and (b, c) AFM
The micro ring resonator prepared by Lukin et al. on the 4H-SICOI platform exhibits a quality factor (Q value) of up to 7.8×105, corresponding to a propagation loss as low as 0.5 dB/cm. In addition, by thermally oxidizing a layer of 20nm SiO2 as a buffer layer, the background fluorescence at the SiC-SiO2 interface can be significantly reduced, allowing for clear detection of color center luminescence.
2. Quantum Light Source and Color Center Enhancement
2.1 Generation of Visible/Near-Infrared Photon Pairs
By utilizing the second-order nonlinearity of 4H-SiC, visible/near-infrared photon pairs can be generated through SPDC process in micro ring resonators. Through modal phase matching (MPM) design, high-order TE20 modes are used as pump light, and fundamental TE00 and TM00 modes are used as signal and idler light, achieving efficient Type II phase matching. The simulation results show that in a waveguide with a width of 500 nm and a height of 700 nm, a signal light of about 700 nm can be generated under 408 nm pumping, and the phase mismatch bandwidth can reach 50 THz.
Fig. 2 Calculation of phase matching conditions for visible/NIR photon pairs used to generate TM polarized signal photons and TE polarized idler photons in a 500nm wide 4H-SiCOI waveguide with heights of (a) 700 nm and (b) 800 nm, respectively
2.2 Strong Coupling Between Color Center and Photon Cavity
Common color centers in 4H-SiC include silicon vacancies (V1, V2) and nitrogen vacancies (NV), with emission wavelengths located in the visible and near-infrared bands. Single color center Purcell enhancement can be achieved through nanobeam photonic crystal cavities. Experiments have shown that when the cavity resonates with the V1 ‘ zero phonon line, the emission lifetime is shortened from 6.66ns to 2.45ns, the intensity is enhanced by 120 times, and the second-order correlation function g2 (0) is 0.08, confirming the single photon property.
3 Nonlinear Frequency Conversion
3.1 Second Harmonic Generation
Efficient SHG can be achieved through modal phase matching in 4H-SiCOI micro ring resonators. The design uses 1555nm TE00 mode pumping to convert to 777.5nm TM20 mode, with a conversion efficiency of 360%W-1. This result indicates that 4H-SiC has significant advantages in integrated nonlinear optical devices.
Fig. 3 Efficient second-order frequency conversion in a micro ring resonator: a. SEM of a ring resonator designed for SHG; b. Numerical simulation of phase matching conditions for 1555nm TE00 and 777.5nm TM20 modes; c. The dependence of the second harmonic power in the output waveguide on the pump power in the input waveguide
3.2 Quantum Frequency Conversion (QFC)
Due to the mismatch between the fiber optic communication band (1.3-1.55μm) and most color center emission bands, quantum frequency conversion has become the key to achieving remote quantum communication. The 4H-SiC platform can achieve efficient single photon frequency conversion through triple resonance micro ring design, and is expected to achieve nearly 100% conversion efficiency with only 300μW of pump power.
With the continuous optimization of material preparation processes (such as reducing injection damage and improving polarization quality) and the improvement of device design theory, the 4H-SiCOI platform is expected to play a core role in building scalable on-chip quantum network nodes, developing high-sensitivity biosensing chips, and achieving hybrid integration of quantum light sources and classical signal processing units.
Whether you need 4H-SiCOI wafer for research or for industrial applications, please contact us email at [email protected] and [email protected].
References:
1. Yi, A., Zheng, Y., Huang, H., Lin, J., Yan, Y., You, T., … & Ou, X. (2020). Wafer-scale 4H-silicon carbide-on-insulator (4H–SiCOI) platform for nonlinear integrated optical devices. Optical Materials, 107, 109990.
2. Zhang, Q., & Poon, A. W. (2025, March). Visible-wavelength quantum photonics in a 4H silicon carbide platform. In Silicon Photonics XX (Vol. 13371, pp. 66-71). SPIE.
3. Lukin, D. M., Dory, C., Guidry, M. A., Yang, K. Y., Mishra, S. D., Trivedi, R., … & Vučković, J. (2020). 4H-silicon-carbide-on-insulator for integrated quantum and nonlinear photonics. Nature Photonics, 14(5), 330-334.