A practical way to link separate nodes in quantum networks is to send photons over the standard telecom fibre network. This requires sub-Poissonian photon sources in the wavelength band around 1550 nm, with photon coherence times sufficient to enable the many interference-based technologies at the heart of quantum networks. Here, we show that droplet epitaxy InAs/InP quantum dots emitting in the telecom C-band can provide photons with coherence times exceeding 1 ns under low power non-resonant excitation, and demonstrate that these coherence times enable near-optimal interference with a C-band polarisation-encoded laser qubit, with visibilities only limited by the quantum dot multiphoton emission. Using entangled photons, we further show teleportation of such qubits in six different bases with average postselected fidelity reaching 88.3 ± 4.0%. Beyond direct applications in long-distance quantum communication, the high degree of coherence in these quantum dots is promising for future spin-based telecom quantum network applications.

链接量子网络中单独节点的一种实用方法是通过标准电信光纤网络发送光子。这就需要在1550 nm左右的波长带中的亚泊松光子源，其光子相干时间足以使量子网络的核心能够使用许多基于干扰的技术。在这里，我们表明在电信C波段中发射的液滴外延InAs / InP量子点可以在低功率非谐振激发下为光子提供超过1 ns的相干时间，并证明这些相干时间使对C的干扰达到最佳状态。波段偏振编码的激光量子比特，其可见性仅受量子点多光子发射的限制。使用纠缠光子，我们进一步展示了这种量子比特在六个不同基数中的隐形传态，平均后选保真度达到88.3±4.0％。