Recent advances in solid-state quantum emitters have led to the realization of quantum communication, quantum teleportation, and quantum simulations. However, to implement such quantum technologies in a practical way, it is essential to interface quantum emitters with low-loss optical platforms, such as fiber optics. So far, there have been several different approaches for coupling single-photon emissions from quantum dots into fiber optics. In particular, integrating quantum dots into nanophotonic structures can significantly enhance light extraction and produce Gaussian like far-field patterns. However, a small numerical aperture of fiber still limits single-photon coupling efficiency. Alternatively, adiabatic coupling between tapered single-photon devices and fibers can provide near-unit coupling efficiency, while the delicate tapered structures cause long-term stability problems. Therefore, none of the previous approaches have realized an efficient and reliable implementation of fiber-integrated quantum emitters. In this study, we demonstrate efficient and compact plug-and-play single-photon sources based on hole-based circular Bragg gratings. A thin-membrane planar resonator with hole gratings produces an ultra-narrow vertical beam whose emission angle matches the small numerical aperture of a single-mode fiber. Using a pick-and-place technique, the fabricated single photon devices can be precisely integrated into the core of a single-mode fiber. The integrated fiber–QD system enables the compact plug-and-play operation of single photons from a source to a detector with high coupling efficiency and long-term stability.
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