We expect our developments to allow scaling up cryogenic quantum computers to millions of qubits, by replacing the non-scalable RF lines nowadays addressing each qubit in the cryostat with optical fibres and suitable optoelectronic converters.

In a shorter term, we also expect our developments to lead to a fast and energy efficient cryogenic replacement of  power hungry GPUs in supercomputers.

aCryComm aims to establish the new field of fast photonic interfaces for cryogenic logic, with an envisaged major impact on HPC and QC. This new technology offers the electronics industry a concrete path towards design, development and production of unconventional processors, outperforming and complementing standard CMOS technology. Our vision is the development of fast and energy-efficient SFQ coprocessors for CMOS high-performance computers (HPCs). From a programmer’s view, this is essentially the same way that GPU clusters are employed in HPC today. Therefore, a vast market for such coprocessors already exists, especially if the cryogenic coprocessors can offer an instruction set similar to GPUs. On the quantum side, while technology is less mature, the scale of quantum computers will only grow in the future. Tightly integrated cryogenic signal processors based on SFQ are a natural solution for enabling this long-term growth. The first step toward this midterm vision is to develop suitable cryogenic data buses. Once these interfaces are available, European stakeholders—including industry and academia—will have a great opportunity to develop the aforementioned SFQ processors thanks to the unique operational model of VTT fab, which offers open access for both R&D and mid-volume contract manufacturing in the same facilities. VTT has a clear opportunity to extend its present offer of Multi-Project-Wafer (MPW) runs – now limited to silicon photonics – to also include superconducting devices and their combination. Open-access runs will help universities and companies to develop complex systems leveraging aCryComm results. In a broader view, our proposed developments include a breadth of innovative and unprecedented combinations of research areas that will enhance Europe’s innovation capacity and competitiveness also in other areas, including Datacom, as we expect our developments to impact also power efficiency of non-cryogenic devices. The nanoscale light source fabrication technology is applicable also to electrically driven non-classical light sources emitting single- or entangled-photons for the needs of integrated quantum photonics and computing. One key development of the project is to use  SNSPDs to drive SFQ and therefore widen the applications of SNSPDs. In addition, this combination will also result in improved SNSPDs read-out for their original applications in quantum communication.