Simple quantum key distribution with qubit-based synchronization and a self-compensating polarization encoder

• DOI: 10.1364/optica.381013
• Publication Date: 2020-02-24T21:00:09Z
• Authors: Costantino Agnesi; Marco Avesani; Luca Calderaro; Andrea Stanco; Giulio Foletto; Mujtaba Zahidy; Alessia Scriminich; Francesco Vedovato; Giuseppe Vallone; Paolo Villoresi
• Keywords: Quantum key distribution

Quantum Key Distribution (QKD) relies on quantum communication to allow distant parties share a secure cryptographic key. Widespread adoption of QKD in current telecommunication networks will require the development simple, low cost and stable systems. However, implementations usually include additional hardware that perform auxiliary tasks such as temporal synchronization polarization basis tracking. Here we present polarization-based system operating at 1550 nm performs compensation by exploiting only already needed for task. Polarization encoding is performed self-compensating Sagnac loop modulator which exhibits high stability lowest intrinsic bit error rate reported so far.The was tested over fiber-optic link, demonstrating tolerance up about 40 dB channel losses. Thanks its reduced requirements quality source, this work represents an important step towards technologically mature