Bridging ultrahigh-Q devices and photonic circuits


Ki Youl Yang, Dong Yoon Oh, Seung Hoon Lee, Qi-Fan Yang, Xu Yi, Boqiang Shen, Heming Wang, and Kerry Vahala. 2018. “Bridging ultrahigh-Q devices and photonic circuits.” Nature Photonics, 12, 5, Pp. 297–302. Publisher's Version


Optical microresonators are essential to a broad range of technologies and scientific disciplines. However, many of their applications rely on discrete devices to attain challenging combinations of ultra-low-loss performance (ultrahigh Q) and resonator design requirements. This prevents access to scalable fabrication methods for photonic integration and lithographic feature control. Indeed, finding a microfabrication bridge that connects ultrahigh-Q device functions with photonic circuits is a priority of the microcavity field. Here, an integrated resonator having a record Q factor over 200 million is presented. Its ultra-low-loss and flexible cavity design brings performance to integrated systems that has been the exclusive domain of discrete silica and crystalline microcavity devices. Two distinctly different devices are demonstrated: soliton sources with electronic repetition rates and high-coherence/low-threshold Brillouin lasers. This multi-device capability and performance from a single integrated cavity platform represents a critical advance for future photonic circuits and systems.Using silicon nitride waveguides processed by plasma-enhanced chemical vapour deposition, full integration of ultrahigh-Q resonators with other photonic devices is now possible, representing a critical advance for future photonic circuits and systems.
Last updated on 07/30/2022