Quantum-Optic Silicon as a Commodity: Extending the Trust Continuum till the Edge of ICT Networks

Informazioni relative al progetto

QOSiLICIOUS

ID dell’accordo di sovvenzione: 101187539

DOI

10.3030/101187539

Data della firma CE 4 Novembre 2024

Data di avvio 1 Febbraio 2025

Data di completamento 31 Gennaio 2029

Finanziato da

• The European Innovation Council (EIC)

Costo totale

€ 4 075 538,50

Contributo UE

€ 4 075 538,50

Coordinato da

AIT AUSTRIAN INSTITUTE OF TECHNOLOGY GMBH
Austria

Periodic Reporting for period 1 - QOSiLICIOUS (Quantum-Optic Silicon as a Commodity: Extending the Trust Continuum till the Edge of ICT Networks)

Periodo di rendicontazione: 2025-02-01 al 2026-01-31

Sintesi del contesto e degli obiettivi generali del progetto

QOSiLICIOUS is a project funded by the European Innovation Council under the Horizon Europe program. The project addresses issues within the field of cybersecurity, with the mission to facilitate the large-scale uptake of Quantum Key Distribution (QKD) – a quantum-based protocol providing information-theoretically secure encryption. While conventional security technologies adopt cryptographic techniques that are inherently vulnerable to potential security breaches, QKD leverages the laws of quantum physics to offer a unique quantum-safe communication solution, proven to be totally immune to security threats.

QKD has been thoroughly investigated for decades, both from a theoretical and practical standpoint. Its transformative potential in the field of communications is widely recognized worldwide, in both academic and industrial environments. However, many QKD demonstrations remain confined to laboratory prototyping or field testing, and a widespread QKD adoption in standard Information and Communication Technology (ICT) infrastructures remains constrained due to two main limiting factors. First, the footprint of QKD components is often too large to enable their operability and integration in diverse real-life environments such as intra-facility networks, datacenters, or even handheld devices. Second, the elevated costs for their mass-scale production drastically reduce the feasibility of large-scale QKD deployment in existing ICT networks.

QOSiLICIOUS’ main mission lies in facilitating the extensive deployment of QKD solutions by leveraging an all-silicon approach that enables photonic and electronic co-integration. The project is set to develop miniaturized photonic QKD components that can be seamlessly integrated into microelectronic circuits, enabling extremely reduced form factors down to sub-square mm for QKD receivers. Additionally, QOSiLICIOUS aims at bringing down the production costs by adopting an all-silicon solution, which eliminates the reliance on rare semiconductor materials and complex heterogeneous integration. It capitalizes on the well-established maturity of the silicon photonic and microelectronic industry to overcome key barriers to chip-scale QKD assembly, effectively developing a novel QKD technology that targets both small form factors and cost-effectiveness.

This all-silicon QKD approach is envisioned for future integration into increasingly interconnected ICT infrastructures. The QKD devices developed within QOSiLICIOUS could therefore be best-suited for deployment across a broad range of ICT environments, from datacenter networks to personal wireless devices. The project aims to address several technological challenges, and benefits from the diverse and complementary background of all the involved partners to transition from early-stage device design to practical use-cases. Its objectives include the integration of optically active quantum light sources into silicon-based platforms for QKD transmitters and (Quantum Random Number Generation) QRNG devices. The project targets ultra-compact designs for seamless integration with electronics – such as footprints <1 square mm for QKD transmitters and <0.01 square mm for QRNG engines. It further addresses the development of fully integrated SiGe detectors in QKD receivers. These technologies will ultimately be tested in large-scale settings, assessing their tolerance to optical losses and security performance in practical deployments.

Lavoro eseguito dall’inizio del progetto fino alla fine del periodo coperto dalla relazione e principali risultati finora ottenuti

During RP1, a number of key achievements have been made by the QOSiLICIOUS team. In relation to the objectives, the following has been obtained:

- Obj. 1: Enhance silicon IC platforms with efficient quantum-optic light emitters
Several CMOS LED designs for monolithic QRNG development were investigated at AIT, including deep-N-well, P-well, and an 8-dot structures. Simulations together with a camera-based characterization of the emitted light intensity was performed, indicating that the LED in P-well is more favorable for SPAD photon detection inside the QRNG pixel. Together with the SPAD and two versions of active quenchers (5 V and 10 V swing), these test structures were brought to tape-out by AIT in January 2026. Final photon count rate measurements will be carried out once the chip with integrated quencher is received from manufacturer X-Fab (expected after April 30 2026).
In parallel, a SiGe light source for the QKD transmitter module was fabricated at IHP and characterized. The results showed LED-like emission in both the C and L telecom wavebands, with output powers suitable for QKD applications. This confirmed the SiGe source as a well-suited candidate for integration into QKD state-preparation circuits as planned in the project.

- Obj. 2: Development of highly miniaturized QRNG pixels and QKD transmitters
Simulations of the CMOS SPAD and its interaction with the integrated Si LED were performed at AIT, and concluded the unsuitability of the initially considered narrow SPAD due to limited carrier collection and high dark count rates. As a consequence, a wider SPAD design was chosen. In parallel, two active quenching circuits (with a 5 V and 10 V swing) were designed at AIT to improve photon detection performance. The complete pixel layout indicates that a true random number rate of 2.5 Mb/s should be possible. The QRNG test structures were brought to tape-out by AIT in January 2026.
Concerning the QKD transmitter module, a QKD transmitter integrating a SiGe light source and a polarization encoding circuit was fabricated at IHP. Initial tests confirmed operation of the source and modulators, with results feeding into the second design cycle where the coupling to the monitor diodes will be optimized to reduce on-chip loss and SiGe the source will be updated to a generation 3 source.

- Obj. 3: Development of a GeSi-based single-photon detector for quantum applications
Following joint design iterations and feasibility assessments for waveguide-coupled SPADs (offering a promising route towards direct integration within silicon photonics chips) between IHP and UGLA, two device concepts were selected for fabrication at IHP, with the first run underway and chips expected in Q2 2026. In parallel, surface-normal SPADs have been further developed at UGLA, with process improvements targeting lower dark count rates, higher operating temperatures, and enhanced detection performance in the C-band.

- Obj. 4: Demonstration of cost-effective QKD in intra-datacenter and access/6G applications
As most tasks relevant to this Objective have not yet started, no measurable progress can be reported at this stage. However, initial requirements for the evaluation of the planned use cases have been defined by NVD together with all partners. Additionally, initial characterizations have been performed by AIT concerning solar-blind short-range QKD and suitability of multi-lane ribbon cables for QKD implementations. Precursor technology has further been employed to perform dynamic key allocation in the context of point-to-multipoint network architectures.

Progressi oltre lo stato dell’arte e potenziale impatto previsto (incluso l’impatto socioeconomico e le implicazioni sociali più ampie del progetto fino ad ora)

QOSiLICIOUS has demonstrated an experimental proof of the world’s first monolithic silicon QKD transmitter, which integrated a silicon-native light source together with a state preparation circuit to implement a polarization-encoded QKD protocol. With this, the project takes an important leap in validating the feasibility of integrated QKD technology that are compatible with the cost credentials of challenging application domains – where state-of-the-art solutions face entry barriers due to use of complex assembly and packaging schemes required when using or pairing III-V semiconductor materials for this purpose. Moreover, the compatibility to obtain positive secure-key rates for operation over class-N1 optical link budgets of passive optical access networks has been experimentally confirmed.