CV Quantum Key Distribution for Free-Space Links

QSpace Labs is building a continuous-variable quantum key distribution stack optimized for atmospheric and near-orbital optical links. The system goal is to preserve theoretically secure key exchange while meeting the practical constraints of deployable free-space hardware.

This paper outlines the architecture assumptions, signal chain, and operating envelope that guide the current platform roadmap.

Conventional public-key infrastructure is exposed to harvest-now, decrypt-later risk. In contrast, QKD derives security from measurement physics, making it attractive for strategic communications where link assurance matters more than software patch cycles.

Continuous-variable approaches align particularly well with commodity photonic components and dense wavelength architectures, opening a path toward practical deployment beyond laboratory demonstrations.

The proposed stack combines stabilized optical sources, modulation control, pointing telemetry, and adaptive post-processing. Each layer is designed to degrade gracefully under atmospheric variation while preserving key rate integrity.

The implementation roadmap assumes integration with classical channels, allowing quantum and data traffic to share tightly managed optical infrastructure.

Early validation is focused on link stability, calibration repeatability, and reconciliation overhead rather than headline laboratory-only rates. The target is a fieldable system that narrows the gap between proof-of-physics and proof-of-deployment.

CV-QKD is a core building block in QSpace Labs’ end-to-end backbone thesis: practical quantum assurance integrated into real optical networks for ground and orbital infrastructure.

QSpace Labs Research — internal concept notes, free-space optical link studies, and quantum networking architecture reviews.