7 September 2020
VLC designs transmitter PIC for CiViQ quantum communications project
As a partner in the project CiViQ, photonic integrated circuit (PIC) design house VLC Photonics of Valencia, Spain (which has experience with various material platforms including silicon photonics, indium phosphide, silicon nitride, PLC and polymer) has designed a new indium phosphide (InP) PIC for secure quantum communications in networks.
The current progress in quantum technologies is expected to promote new opportunities with integrated photonics, opening up market prospects in secure communication, aerospace, defence, sensing and light detection & ranging (LiDAR).
As part of the European Quantum Flagship initiative – and funded by the European Union’s Horizon 2020 research and innovation program under grant no. 820466 - the CiViQ project focuses on cost-efficient, high-integration and high-performance quantum communication technologies to deploy continuous-variable quantum key distribution (QKD) into the optical telecommunications network infrastructure. In this context, PICs can play a crucial role.
CiViQ hence unites, for the first time, a broad interdisciplinary community of 21 partners, involving major telecom firms, integrators and developers of QKD. The work aims to advance both QKD technology itself and the emerging 'software network’ approach to lay the foundations for future seamless integration of the two.
As a design house that supports PIC development, VLC Photonics has expertise in photonic building blocks and system design, circuit layout generation and validation, foundry consultancy and fabrication management, and bare-die characterization and testing, as well as providing support in packaging.
In the CiViQ project, VLC is facilitating the transformation of a bulky optical system (built in a lab) into a photonic integrated design circuit layout in a standard 4mm x 6mm cell-size, sufficiently flexible to satisfy the various requirements from QKD system partners. Taking advantage of the ‘generic purpose’ process available for prototyping and concept validation, the chips can then be fabricated through a JePPIX (Joint European Platform for Photonic Integration of Components and Circuits) multi-project wafer (MPW) run of the InP foundry at CiViQ partner Fraunhofer Heinrich-Hertz-Institut (HHI) of Berlin, Germany (a research center for mobile and stationary communication networks).
Conceived by QKD system partners Instituto de Ciencias Fotónicas (ICFO, Spain), Centre National de la Recherche Scientifique (CNRS, France), Max Planck Institute for the Science of Light (MPL, Germany), Technical University of Denmark (DTU, Denmark) and Huawei Technologies Düsseldorf (HWDU, Germany) together with HHI and VLC, the first generation of the continuous-variable QKD transmitter consists of a low-linewidth laser and the modulator PIC, which includes a high-extinction electro-absorption modulator (EAM), an IQ modulation scheme and a variable optical attenuator (VOA). The compact design exhibits a good compromise between system complexity, redundant optical paths for monitoring the performance, and distribution of electrical paths for driving the components.
After VLC has provided the specific design of the chip and HHI has fabricated it, the modulation system of the transmitter will be characterized by VLC, as well as by ICFO and CNRS, to consider the functionalities as an independent component device. In a second stage, the integrated narrow-linewidth laser, currently being developed by HHI, will also be integrated in the transmitter. This integrated transmitter will be then used in continuous-variable QKD systems developed within CiViQ to meet network security demands.