Ultrabroadband Quantum-Secured Communication

TL;DR

This paper introduces a high-speed quantum-secured communication protocol using ultrabroadband photons, achieving gigabit per second rates over 50 km, and enhances security with channel monitoring and advanced sources.

Contribution

It presents a novel two-way protocol combining amplified spontaneous emission and phase-shift keying for ultrabroadband quantum communication with high secure data rates.

Findings

Achieves 3.5 Gbps secure communication at 50 km

Enables 2 Gbps quantum key distribution with added channel monitoring

Significantly increases secure key rates over long distances

Abstract

We propose a two-way secure-communication protocol in which Alice uses an amplified spontaneous emission source while Bob employs binary phase-shift keying and an optical amplifier. Against an eavesdropper who captures all the light lost in fibers linking Alice and Bob, this protocol is capable of 3.5 Gbps quantum-secured direct communication at 50 km range. If Alice augments her terminal with a spontaneous parametric downconverter and both Alice and Bob add channel monitors, they can realize 2 Gbps quantum key distribution at that range against an eavesdropper who injects her own light into Bob's terminal. Compared with prevailing quantum key distribution methods, this protocol has the potential to significantly increase secure key rates at long distances by employing many ultrabroadband photons per key bit to mitigate channel loss.