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 gcorr(2)(0)=(5.9±0.8)×10−3$g_{{\mathrm{corr}}}^{(2)}\;(0) = ({5.9 \pm 0.8})\; \times {10^{ - 3}}$ (background‐corrected) or graw(2)(0)=(9.5±1.4)×10−2$g_{{\mathrm{raw}}}^{(2)}(0)\; = ({9.5 \pm 1.4})\; \times {10^{ - 2}}{\mathrm{\;}}$(raw data). The decay time of the QD is measured to be τ=440${\mathrm{\tau \;}} = {\mathrm{\;}}440$ 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. [ABSTRACT FROM AUTHOR]