Free-Space Quantum Key Distribution

TL;DR

This paper discusses free-space quantum key distribution, highlighting its basis in fundamental physics, and presents an overview of an experimental free-space quantum communication link developed in Spain as a cost-effective alternative to fiber optics.

Contribution

It introduces the development and analysis of a free-space quantum communication link, expanding quantum cryptography applications beyond fiber optic systems.

Findings

Demonstrated a working free-space quantum communication link

Showed cost-effectiveness compared to fiber optic systems

Validated the feasibility of free-space quantum key distribution

Abstract

Based on the firm laws of physics rather than unproven foundations of mathematical complexity, quantum cryptography provides a radically different solution for encryption and promises unconditional security. Quantum cryptography systems are typically built between two nodes connected to each other through fiber optic. This chapter focuses on quantum cryptography systems operating over free-space optical channels as a cost-effective and license-free alternative to fiber optic counterparts. It provides an overview of the different parts of an experimental free-space quantum communication link developed in the Spanish National Research Council (Madrid, Spain).