Aluminum nitride integration on silicon nitride photonic circuits: a hybrid approach towards on-chip nonlinear optics

Aluminum nitride (AlN) is an emerging material for integrated quantum photonics due to its large chi((2)) nonlinearity. Here we demonstrate the hybrid integration of AlN on silicon nitride (SiN) photonic chips. Composite microrings are fabricated by reactive DC sputtering of caxis oriented AlN on top of pre-patterned SiN. This new approach does not require any patterning of AlN and depends only on reliable SiN nanofabrication. This simplifies the nanofabrication process drastically. Optical characteristics, such as the quality factor, propagation losses and group index, are obtained. Our hybrid resonators can have a one order of magnitude increase in quality factor after the AlN integration, with propagation losses down to 0.7 dB/cm. Using finite-clement simulations, phase matching in these waveguides is explored. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

The study demonstrates the hybrid integration of AlN on SiN photonic chips, fabricating composite microrings by reactive DC sputtering of AlN on pre-patterned SiN. This approach simplifies nanofabrication and significantly improves the quality factor of hybrid resonators, reducing propagation losses.