Low temperature, and high-quality silicon carbide photonics for hybrid photonic integration

Hybrid integration of SiC has enormous potential for telecommunication applications, nonlinear photonics, sensing, and quantum photonics. Amorphous SiC (a-SiC) is particularly interesting as it has enormous potential to be deterministically integrated with most established photonic platforms. However, high-quality a-SiC photonics were missing, and compatibility with CMOS or III-V platforms requires low-temperature deposition. We have recently developed high-quality a-SiC photonics at low temperatures (⪅150°C) and demonstrated ring resonators with quality factors exceeding 5x10⁵ (waveguide propagation loss of 0.78 dB/cm). Low-temperature deposition allowed high-performance photonic circuits by liftoff. Moreover, process compatibility made the integration of a-SiC with lithium niobate (LN) and silicon nitride (SiN) possible. On a-SiC/LN platform, we achieved electro-optical tunability of 3.4 pm/V (3mm tuning length). Furthermore, on a-SiC/SiN platform we showcase coupling efficiencies (between a-SiC and SiN), exceeding 90%, making the combination of ultralow loss (SiN) and dense (a-SiC) photonics possible.