On-demand generation of entangled photon pairs in the telecom C-band for fiber-based quantum networks

TL;DR

This paper demonstrates on-demand generation of high-fidelity entangled photon pairs in the telecom C-band using quantum dots, enabling secure fiber-based quantum communication and scalable quantum networks.

Contribution

It introduces a robust phonon-assisted excitation scheme for quantum dots to produce entangled photons on demand with high concurrence and fidelity.

Findings

Achieved 91.4% concurrence in entangled photon pairs.

Fidelity of 95.2% to the Bell state +.

Demonstrated potential for long-distance quantum communication.

Abstract

On-demand sources of entangled photons for the transmission of quantum information in the telecom C-band are required to realize fiber-based quantum networks. So far, non-deterministic sources of quantum states of light were used for long distance entanglement distribution in this lowest loss wavelength range. However, they are fundamentally limited in either efficiency or security due to their Poissonian emission statistics. Here, we show on-demand generation of entangled photon pairs in the telecom C-band by an InAs/GaAs semiconductor quantum dot. Using a robust phonon-assisted excitation scheme we measure a concurrence of $91.4\,\%$ and a fidelity of $95.2\,\%$ to $\Phi^+$. On-demand generation of polarization entangled photons will enable secure quantum communication in fiber-based networks. Furthermore, applying this excitation scheme to several remote quantum dots tuned into resonance will enable first on-demand entanglement distribution over large distances for scalable real-life quantum applications.