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

## TL;DR

This paper demonstrates that telecom C-band quantum dots can produce highly coherent photons suitable for quantum teleportation and quantum networks, with coherence times exceeding 1 ns and high teleportation fidelity.

## Contribution

It introduces highly coherent InAs/InP quantum dots emitting in the telecom C-band, enabling quantum teleportation with high fidelity and advancing quantum communication technologies.

## Key findings

- Photon coherence times >1 ns under non-resonant excitation
- Teleportation fidelity of 88.3% in six bases
- High interference visibility limited by multiphoton emission

## Abstract

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 telecom wavelength band around 1550 nm, where the photon coherence time has 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 dots emitting in the telecom C-band can provide photons with coherence times exceeding 1 ns even under non-resonant excitation, more than a factor two longer than values reported for shorter wavelength quantum dots under similar conditions. We demonstrate that these coherence times enable near-optimal interference with a C-band 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 fidelity reaching 88.3$\pm$4%. 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.