Quantum teleportation using highly coherent emission from telecom C-band quantum dots

A practical way to link separate nodes in quantum networksis to send photons over the standard telecom fibre network. This requires sub-Poissonian photon sources in the telecom wavelength band around 1550 nm, where the photon coherence timehas to be sufficient to enable the many interference-based technologies at the heart of quantum networks. Here, we show that droplet epitaxy InAs/InP quantum dotsemitting in the telecom C-bandcan provide photons with coherence timesexceeding 1 ns even under non-resonant excitation, more than a factor two longer than values reported for shorter wavelength quantum dotsunder similar conditions. We demonstrate that these coherence timesenable near-optimal interference with a C-bandlaser qubit, with visibilities only limited by the quantum dotmultiphoton emission. Using entangled photons, we further show teleportationof such qubits in six different bases with average fidelity reaching 88.3$\pm$4%. Beyond direct applicationsin long-distance quantum communication, the high degreeof coherencein these quantum dotsis promising for future spin based telecom quantum networkapplications.