TILBA®-OGS and QKD: Building Confidence in a Quantum-Secure Future

Quantum Security and Optical Links: Complementary Paths in Space Communications

This promise isn’t just theoretical. China’s 2016 launch of the Micius satellite remains a defining moment, demonstrating the viability of QKD over thousands of kilometers. Since then, activity has increased globally, with governments and commercial players exploring space-based QKD to future-proof sensitive communications. And yet, enthusiasm must be balanced with a sober view of the current limitations: limited key rates, reliance on trusted nodes, and early-stage infrastructure.

Meanwhile, classical optical communications have reached an impressive level of maturity. Narrow-beam laser links offer extremely high data rates, reduced risk of interception, and improved energy efficiency over traditional radio frequencies. The space sector has moved rapidly to embrace this technology. SpaceX, Kepler Communications, and government agencies like NASA have all demonstrated operational optical inter-satellite and ground links, some with record-setting results.

Toward Compatibility : Why TILBA®-OGS is Positioned for the Quantum Leap

At Cailabs, we believe the key to securing tomorrow’s space communications lies in platforms designed for flexibility, reliability, and future compatibility. Our TILBA® Optical Ground Station (OGS) embodies this philosophy.

Initially developed to unleash the full potential of laser communications for LEO satellite links, TILBA® is already operationally robust. It is equipped with an 800 mm diameter main telescope with Nasmyth focus, high-precision Alt-Az tracking mounts achieving less than 1 arcsecond RMS open-loop accuracy, and a sophisticated multi-stage pointing, acquisition, and tracking system​.

These features ensure extremely high stability and precision, both of which are prerequisites not just for high-speed classical laser links, but also for the more delicate requirements of quantum communications.

Moreover, TILBA® integrates Cailabs’ proprietary turbulence mitigation technologies, which are essential for maintaining link quality through the atmosphere. On the receive side, the TILBA®-ATMO module recombines up to 45 optical modes at kilohertz bandwidths without using moving parts​. On the transmit side, our TILBA®-IBC technology employs spatial diversity to mitigate turbulence effects during uplink, reducing outage probability while remaining eye-safe. These features position TILBA® among the very few ground stations capable of operating reliably even under challenging atmospheric conditions.

This technical foundation makes TILBA® an ideal candidate for future hybrid operations where high-throughput classical links are augmented with QKD sessions.

The station’s modularity allows for the integration of quantum-compatible detection chains and synchronization systems. Furthermore, our stations are being delivered as part of the Obs2OGS project, in particular for ground stations that will be compatible with Eagle-1 Laser Communication Terminals — a European flagship mission aiming to demonstrate secure space-based QKD​.

This proves that TILBA® is not just theoretically ready: it is being actively deployed in projects that define the future of secure optical communication.

Thanks to its multi-mission architecture, TILBA® supports various satellite platforms, modulation formats, and mission profiles — from ISR data downlinks to high-throughput commercial relay links — while leaving a clear path toward quantum-grade encryption capabilities. In the short term, it delivers secure, high-speed classical optical communications. In the medium to long term, it offers a bridge to QKD-enhanced systems without the need for full redesigns.

By delivering platforms that are operational today and future-proofed for tomorrow, Cailabs is helping to transform what secure satellite communications will look like in the quantum era. The evolution towards hybrid optical-QKD networks will be gradual, but thanks to TILBA® and projects like Obs2OGS, that future is already being built.

By Isidor Toukam

Isidor Toukam is a third-year engineering student at Institut d’Optique with a strong interest in industrial lasers, both technically and commercially. He is currently completing an R&D Marketing internship at Cailabs, where he contributes to the creation of technical marketing content for the TILBA® and CANUNDA product lines.