European Commission logo
English English
CORDIS - EU research results

Quantum Emitters for Telecommunication in the O-Band

Periodic Reporting for period 2 - QuanTELCO (Quantum Emitters for Telecommunication in the O-Band)

Reporting period: 2020-10-01 to 2023-09-30

A quantum internet will revolutionize communication technology by exploiting phenomena from quantum physics. Despite recent successes in the deployment of secure quantum cryptographic keys, the lack of telecom-wavelength repeaters operating at the quantum level presents a major bottleneck to realizing a global-scale quantum communication network. The EU-funded QuanTELCO project will overcome this challenge by exploiting specific spin centres in silicon carbide which possess strong optical transitions in the telecom O-band. These quantum emitters furthermore host electronic and nuclear spins that can act as memories in quantum repeater nodes. Such a breakthrough should help create robust, transcontinental quantum information links compatible with existing infrastructure, ushering in the era of quantum-encrypted communications and networked quantum computing in Europe.
Despite recent successes in the deployment of secure quantum cryptographic keys, the unavailability of telecom-wavelength repeaters operating at the quantum level presents a major bottleneck towards a global-scale quantum communication network. QuanTELCO will overcome this bottleneck by employing a radically transformative approach based on telecom-wavelength spin centres in silicon carbide, recently discovered by our consortium. These centres uniquely possess strong optical transitions in the telecom O-band (1260-1360 nm), in a material widely used by the micro-electronics industry. QuanTELCO will exploit a mature material platform (silicon carbide), fully compatible with standard industrial micro-electronic fabrication processes. Their emission wavelength allows direct, low-loss propagation in existing telecom networks without the detrimental losses caused by wavelength conversion. These emitters host electronic and nuclear spins which can act as memories in quantum repeater nodes. QuanTELCO will perform an in-depth study of these properties in order to demonstrate all key elements of quantum networking. QuanTELCO will distil the project results to deliver a roadmap for commercial deployment based on real-world, actionable insight. In summary, the project aim is to provide the breakthrough required for the creation of robust, transcontinental quantum information links, compatible with existing infrastructure, thereby ushering in the era of physically secure encryption and networked quantum computation across Europe.
WP1- Quantum photonics with single emitters

Preliminary work investigated the properties of ensembles by a combination of optical spectroscopy and optically-detected magnetic resonance (HWU, UNIVIE) and theoretical modelling (BME).
Progress in first period:
• Theoretical progress in identifying the best candidates and their properties
• Two experimental setups in operation
Progress in second period:
• Single-photon emitter at telecom wavelength detected
• Spin-dependent optical transitions theoretically identified and observed
• In-depth understanding of charge-state dynamics
• Removed inhomogeneous distribution by isotopic purification
• Potential for spin-photon entanglement assessed

WP2- Telecom quantum memory with spin ensembles

RUG and UNIVIE extended their recent experimental characterization of optical and spin properties of Mo/V ensembles in SiC, with theoretical support by BME and related work in WP1.
Progress in first period:
• Experiments running, ensemble samples delivered first results
• T1 of molybdenum ions in 6H SiC measured at low temperature.
• Extensive collaboration between theory and experiment developed.
Progress in second period:
• Measurement of T1 in vanadium ensembles at ultralow T (0.1 K…2 K)
• Detailed optical spectroscopy of vanadium ensembles performed
• Coherent manipulation and pulsed control of electron spin achieved
• Implementation of single-mode waveguides in SiC containing colour centres
• Thorough theoretical models of transition metals in SiC.

WP3 –Device Technology and Telecom Integration

Led by SOUTHAMPTON, this WP contains all tasks related to design and fabrication of quantum opto-electronic devices for WP1 and WP2.
Progress in first period:
• High-purity SiC samples demonstrated
• Membrane fabrication developed
• Optimizing fabrication of waveguides and Fabry-Pérot cavities.
Progress in second period:
• Ultrahigh-finesse microcavities in O-band
• High-purity SiC samples implemented with single spin centres
• Membrane fabrication optimized
• Developed parallelized solid-immersion lens fabrication
• Fabrication of nanopillars
• Fabrication of waveguides and Fabry-Pérot cavities containing spin centres.

WP4- QuanTELCO management, exploitation, dissemination and communication

The coordinator leads this work package, and thus facilitates, coordinates and ensures the execution of the project in close and positive cooperation between project partners to achieve the project goals, outputs and deliverables. The coordinator is the responsible body and contact point for the European Commission (EC).
Progress in first period:
• Kick-off meeting
• Project website, social media accounts and introductory video online
• Data management plan drafted
• Scientific Advisory Board meetings held online
• Dissemination and Exploitation plan submitted.
Progress in second period:
• Project website and social media accounts actively maintained
• Scientific Advisory Board meetings held online
• Strategy adapted according to external and scientific factors
• Interactions with potential industrial partners
• Consortium meetings and final workshop held
• White paper with roadmap completed.
The project builds upon decades of research in materials science, microtechnology, quantum communication, and photonics, bringing together vast expertise in each of these disciplines in order to achieve a dramatic leap in performance for quantum communication infrastructure, by combining the most advantageous aspects of a multitude of approaches.
The project has broken new ground towards overcoming the current bottlenecks in the field of quantum networking, by developing new technology based on a novel physical system that combines favourable spin properties and direct interfacing to telecom-wavelength photons, in a material with excellent prospects for system integration.
The success of this project will provide a strong motivation for quantum networking researchers to adopt impurities in SiC as the leading system for quantum repeaters compatible with the most advanced telecom optical networks and industrial semiconductors.
The results of QuanTELCO thereby strengthen the EU's scientific leadership in quantum technology and offer prospects for kick-starting a quantum communication industry on the basis of the strong and rapidly-growing SiC semiconductor industry.
Cryogenic experimental setup