Silicon nitride (SiN) platform shows great promise for linear and nonlinear integrated photonics, thanks to its moderate refraction index (~2.0), low sidewall roughness, CMOS compatibility process, and wide transparent windows from visible to mid-IR wavelengths. In particular, SiN microrings can achieve extremely high quality factors (Q). The field enhancement in these high Q microrings is the key to many on-chip nonlinear phenomena, including Kerr frequency combs, optical parametric oscillation, and photon pair generation. The low propagation of SiN waveguides enables bio-medical, sensing, and LiDAR applications.
In our group, we have developed in-house nanofabrication for the SiN platform. We can deposit SiN layers with low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced chemical vapor deposition (PECVD). We have designed and fabricated various SiN components, including waveguides, grating couplings, microrings, and edge couplers. The quality factor of the fabricated SiN microring can be as high as 6.2×105.
