Bottom-up Single Quantum Dots in Microring Resonators for On-Chip Integrated Single Emitters

Ring resonators, enabling various quantum functionalities, are crucial components in on-chip quantum photonic integrated circuits. However, the current challenge of on-chip quantum photonics integration is the complicated nondeterministic fabrication processes that lack scalability and repeatability. To overcome these issues, we develop a bottom-up approach to deterministically grow single InAsP quantum dots in InP microrings in a single epitaxial run for on-chip single-photon emission applications. The quantum dots are incorporated into high quality factor microring cavities. The coupling of the quantum dot emission into the whispering gallery mode of the ring results in Purcell-enhanced single-photon emission. Furthermore, we engineer the emitter–cavity coupling efficiency by optimizing the whispering gallery mode spacing, demonstrating high coupling probability and multiwavelength single-photon emissions with larger rings. Our technology provides a pathway toward on-chip integrated single-photon emitters for a miniaturized quantum information processing platform.