# A cost-effective measurement-device-independent quantum key distribution system for quantum networks

## TL;DR

This paper demonstrates a cost-effective, practical measurement-device-independent quantum key distribution system using commercial hardware, capable of supporting quantum networks over 100 km.

## Contribution

It introduces a low-cost MDI-QKD system with commercial components and active feedback, enabling scalable quantum networks.

## Key findings

- System operates effectively over 100 km fiber links.
- Use of commercial hardware reduces costs and complexity.
- Active feedback maintains system performance over time.

## Abstract

We experimentally realize a measurement-device-independent quantum key distribution (MDI-QKD) system based on cost-effective and commercially available hardware such as distributed feedback (DFB) lasers and field-programmable gate arrays (FPGA) that enable time-bin qubit preparation and time-tagging, and active feedback systems that allow for compensation of time-varying properties of photons after transmission through deployed fibre. We examine the performance of our system, and conclude that its design does not compromise performance. Our demonstration paves the way for MDI-QKD-based quantum networks in star-type topology that extend over more than 100 km distance.