A Chip-Scale Transmitter Module for Real-Time Continuous-Variable QKD

TL;DR

This paper presents a compact, chip-scale transmitter module for continuous-variable quantum key distribution, enabling real-time operation and long-distance secure communication with significantly reduced optical size.

Contribution

The work introduces a hybrid chip-scale transmitter for CV-QKD, combining commercial components to achieve real-time operation and extend communication distance.

Findings

Secret-key generation over 102 km fiber

Size reduction of optical components by 95%

Real-time operation eliminates offline post-processing

Abstract

Continuous-variable quantum key distribution (CV-QKD) enables secure communication over standard telecom infrastructure, yet its scaling is stalled by bulky, discrete optical hardware. We address this bottleneck by demonstrating a real-time CV-QKD system driven by a chip-scale hybrid transmitter built from commercial telecom components. By integrating a micro-optic external-cavity laser with a monolithic photonic integrated IQ modulator, we provide high performance, enabling secret-key generation over 102 km of optical fiber, while reducing the size of the optics by 95%. Moreover, real-time operation overcomes the offline post-processing bottlenecks of experimental setups. This work bridges laboratory demonstrations and field-deployable technology, with a scalable architecture for cost-effective quantum networks.