Frequency-bin quantum encoding shows great promise for quantum communication given its high-dimensional scaling, compatibility with photonic integrated circuits and synergy with classical optical communication technology. However, to date all demonstrations have been performed over single-mode and static channels, while the transmission over fluctuating and turbulent channels has not been addressed. We propose and demonstrate a novel approach that leverages field-widened interferometers to decode frequency-bins transmitted over free-space channels without any adaptive optics or modal filtering. Moreover, we investigate the phase stability requirements so that frequency-bin encoding could be feasible for satellite to ground quantum links. Our passive approach expands the versatility of frequency-bin encoding, paving the way towards long-range and fluctuating channels.
@article{arxiv.2412.06104,
title = {Feasibility study of frequency-encoded photonic qubits over a free-space channel},
author = {Stéphane Vinet and Wilson Wu and Yujie Zhang and Thomas Jennewein},
journal= {arXiv preprint arXiv:2412.06104},
year = {2024}
}