# Experimental 4-intensity decoy-state quantum key distribution with asymmetric basis detector efficiency

## TL;DR

This paper demonstrates a high-rate quantum key distribution protocol that accounts for asymmetric basis detector efficiencies, significantly improving key rates and challenging previous assumptions of equal basis efficiencies.

## Contribution

It introduces the first implementation of 4-intensity decoy-state QKD with asymmetric basis detector efficiency, enhancing practical applicability.

## Key findings

- Achieved 1.9 to 33.2 times higher key rates with asymmetry.
- Ruled out the assumption of equal basis detector efficiencies.
- Paved the way for more practical QKD systems.

## Abstract

The decoy-state method has been developed rapidly in quantum key distribution (QKD) since it is immune to photon-number splitting attacks. However, two basis detector efficiency asymmetry, which exists in realistic scenarios, has been ignored in the prior results. By using the recent 4-intensity decoy-state optimization protocol, we report the first implementation of high-rate QKD with asymmetric basis detector efficiency, demonstrating 1.9 to 33.2 times higher key rate than previous protocols in the situation of large basis detector efficiency asymmetry. The results ruled out an implicitly assumption in QKD that the efficiency of Z basis and X basis are restricted to be same. This work paves the way towards a more practical QKD setting.