Ultra-high-Q UV microring resonators based on a single-crystalline AIN platform

Development of low-loss photonic components in the ultraviolet (UV) band will open new prospects for classical and quantum optics. Compared with other integrated platforms, aluminum nitride (AIN) is particularly attractive as it features an enormous bandgap of similar to 6.2 eV and intrinsic chi((2)) and chi((3)) susceptibilities. In this work, we demonstrate a record quality factor of 2.1 x 10(5) (optical loss similar to 8 dB/cm) at 390 nm based on single-crystalline AIN microrings. The low-loss AIN waveguide represents a significant milestone toward UV photonic integrated circuits as it features full compatibility for future incorporation of AlGaN-based IN emitters and receivers. On-chip UV spectroscopy, nonlinear optics, and quantum information processing can also be envisioned. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement