Quantum key distribution (QKD) is nowadays a well established method for generating secret keys at a distance in an information-theoretic secure way, as the secrecy of QKD relies on the laws of quantum physics and not computational complexity. In order to industrialize QKD, low-cost, mass-manufactured and practical QKD setups are required. Hence, photonic and electronic integration of the sender's and receiver's respective components is currently in the spotlight. Here we present a high-speed (2.5 GHz) integrated QKD setup featuring a transmitter chip in silicon photonics allowing for high-speed modulation and accurate state preparation, as well as a polarization-independent low-loss receiver chip in aluminum borosilicate glass fabricated by the femtosecond laser micromachining technique. Our system achieves raw bit error rates, quantum bit error rates and secret key rates equivalent to a much more complex state-of-the-art setup based on discrete components.
@article{arxiv.2211.11560,
title = {High-speed integrated QKD system},
author = {Rebecka Sax and Alberto Boaron and Gianluca Boso and Simone Atzeni and Andrea Crespi and Fadri GrÜnenfelder and Davide Rusca and Aws Al-Saadi and Danilo Bronzi and Sebastian Kupijai and Hanjo Rhee and Roberto Osellame and Hugo Zbinden},
journal= {arXiv preprint arXiv:2211.11560},
year = {2022}
}