Polarization basis tracking scheme for quantum key distribution with revealed sifted key bits

TL;DR

This paper presents a polarization-basis tracking scheme for quantum key distribution that uses only revealed sifted key bits, reducing error rates and improving efficiency without extra reference signals.

Contribution

The proposed scheme enables polarization basis calibration using only sifted key bits, eliminating the need for additional reference light or transmission interruptions.

Findings

Achieved an average QBER of 2.32% over 24 hours

Demonstrated continuous operation with stable error rates

Validated the scheme with a fiber BB84 QKD prototype

Abstract

Calibration of the polarization basis between the transmitter and receiver is an important task in quantum key distribution (QKD). An effective polarization-basis tracking scheme will decrease the quantum bit error rate (QBER) and improve the efficiency of a polarization encoding QKD system. In this paper, we proposed a polarization-basis tracking scheme using only unveiled sifted key bits while performing error correction by legitimate users, rather than introducing additional reference light or interrupting the transmission of quantum signals. A polarization-encoding fiber BB84 QKD prototype was developed to examine the validity of this scheme. An average QBER of 2.32% and a standard derivation of 0.87% have been obtained during 24 hours of continuous operation.