Silicon Carbide (SiC) is a CMOS-compatible semiconductor material that holds promise for realizing the monolithic integration of electronics and photonics with low fabrication costs via CMOS foundry. The non-centrosymmetric crystal structures of SiC grant both second-order and third-order nonlinear effects, enabling an efficient light frequency conversion and on-chip generation of nonclassical light states. SiC exhibits the Pockels effects leading to low loss, ultrafast, and broad bandwidth data transmission.
A significant obstacle in the practical application of Silicon Carbide photonics is fabricating ultralow optical loss SiC thin films on the wafer scale. Now, researchers have developed an ultralow loss 4H-SiCOI platform with a record-high-Q factor of 7.1 × 106, using wafer-bonding and thinning techniques.
The researchers used high-Q resonators to demonstrate various nonlinear processes, including generating multiple harmonics up to the fourth-order, cascaded Raman lasing (Raman shift of 204.03 cm−1), and Kerr frequency comb (1300 to 1700 nm at 13 mW). They observed broadband frequency conversions, including second-, third-, fourth- harmonic generation (SHG, THG, FHG).