Exail and Thales partner on new quantum communications hardware

09 Mar 2023

French firms providing industrial expertise for rapid development of ready-to-deploy QKD systems in Europe.

QKISS

Exail, the France-based technology company, is leading a new European-funded project hoping to develop ready-to-deploy quantum key distribution (QKD) systems for ultra-secure optical communications.

The Quantum Key Industrial SystemS (QKISS) project, which officially kicked off in January, also features defense giant Thales and is aiming to produce high-performance, secure and certifiable systems within three years.

Working alongside Exail and Thales will be two leading academic teams, from Université Paris-Saclay and Sorbonne Université.

Strategic autonomy
According to Exail, the European Commission’s Quantum Communication Infrastructure (EruoQCI) initiative is aiming to build a secure quantum communication infrastructure spanning the entire European Union, including overseas territories.

However, at the moment Europe lacks the kind of established QKD hardware providers that would be needed for total strategic autonomy.

In a bid to help solve that problem, the objective of the QKISS project is to implement a complete, qualified telecom link supporting encrypted communications developed by the French partnership.

Exail says that the effort encompasses manufacturing of opto-electronic components, development of specialized signal processing and coding algorithms, all the way up to full system integration, field demonstrations, and evidence of compatibility with telecom network systems.

The company, which was created last year by the merger of photonics-focused iXblue and industrial automation firm ECA Group, already provides key components for QKD in the form of single-frequency seed lasers, optical modulators, and variable optical attenuators, for both the transmit and receive side of QKD systems.

AliX and BeatriX
QKD systems designers typically refer to “Alice” and “Bob” as the sender and recipient of encrypted information, but QKISS will see a particularly Francophone take on those names. Baptiste Gouraud, R&D engineer and project manager at Exail, explained in a company announcement:

“In practice, QKISS will [result in] implementation of a laser-telecom link between a transmitter called “AliX” and a receiver called ”BeatriX” thanks to optical fibers.

“Using the same technique as in long-haul optical communications, information will be transmitted through coherent modulation of light: it will be encoded in the amplitude and phase of the electromagnetic field, but will be protected by the quantum detection noise.

“Coherent homodyne or heterodyne detection will be used to retrieve the quadrature value of the signal to read the key into it.”

CV-QKD focus
Philippe Grangier, head of the Quantum Optic Group at the Institut d’Optique, pointed out that the QKISS project would utilize continuous-variable quantum key distribution (CV-QKD), building on two decades of academic research into the approach.

Unlike regular QKD, CV-QKD does not require costly low-temperature single-photon avalanche detectors (SPADs), with Grangier saying: “After tremendous progress over the years, involving both academic and industry partners, the technology is now mature enough for industrial deployment.”

Eleni Diamanti, CNRS Senior Researcher and team leader at Sorbonne’s LIP6 lab, added that QKISS would be able to build on recent QKD-related developments under EU-funded projects such as CiViQ, which included a number of Europe’s largest telecoms firms, as well as the German subsidiary of China’s Huawei.

The partners say that QKISS will target a low-cost but high-rate implementation, suitable for metropolitan use-cases at communication speeds with a modulation rate of hundreds of megabaud (MBd), and a secure key rate in the realm of megabits per second (Mbit/s).

“After an industrialization phase, QKISS systems will be available for deployment in the EuroQCI and applications relying on private communications: e-banking, e-health, government communication or the management and protection of critical infrastructure,” they predict.