Plug-and-Play Fiber-Coupled Quantum Dot Single-Photon Source via Photonic Wire Bonding

The collection of single-photon emission from a quantum dot (QD) in a Bragg waveguide through a photonic wire bond (PWB) via free-space resonant frequency pumping at 1.6 K is demonstrated. The in-fiber single photons show a small multiphoton contribution, quantified by a low second order photon autocorrelation value of g(corr)((2))(0)=(5.9 +/- 0.8)x10(-3) (background-corrected) or graw((0))((2)) = (9.5 +/- 1.4)x10(-2) (raw data). The decay time of the QD is measured to be tau=440 ps. The PWB obviates the need for in-cryostat alignment of the single-photon source with an optical fiber and thus offers a route to scalable integration of quantum photonic devices in a cryogenic environment. Uniquely, the approach combines the QD-waveguide technique, enabling resonant driving of individual QDs without the need for cross-polarization filtering, and the PWB for deterministic, alignment-free coupling of single-photon sources to optical fibers. The combination of a single-photon source in a ridge waveguide with a photonic wire bond (PWB) connected to the end-facet is demonstrated. After cooling the sample to 1.6 K, decay time and second-order autocorrelation under pulsed, resonant optical excitation are analyzed. The findings herein highlight the possibility of using PWBs at low temperatures as an interface for single-photon collection.image