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Abstract

Over the past 50 years, data generation and consumption have been growing at an exponential rate. Traditional technologies for data dissemination across various length scales have either reached or are approaching their capacity limits. Optical free-space communications are anticipated to relieve this burden from radio-based wireless communications, by enabling seamless integration of satellite and ground-based systems and delivering a huge increase in wireless data transport capacity across all length scales. To support future applications-such as high-resolution Earth observation, 5G and beyond wireless connectivity, and data-intensive services-a new paradigm for wireless connectivity is required. In response to this need, the 5-year research program "Optical Wireless Superhighways: Free Photons (at Home and in Space)" was launched in 2021, with funding from the Dutch Research Council (NWO) and support from a consortium of knowledge institutes and companies within the Dutch optical wireless ecosystem. The program involves 15 PhD candidates across five universities working closely with an engaged user community. A primary goal of the program is to develop a unified, multi-technology network incorporating satellites as essential components next to a range of terrestrial and user access networks. Both exploratory and applied research are being conducted on critical aspects of deploying optical communications to provide a vast extension to radio frequencies for wireless connectivity. Using the concept of 5G as a "network of networks", the program seeks to seamlessly integrate satellite communications with terrestrial and user access networks, enabling satellite-to-satellite Network Functions Virtualization (NFV) and Software Defined Networking (SDN). This streamlined integration between terrestrial and satellite networks offers new growth opportunities for the ever-expanding Internet of Things (IoT). Leveraging the vast available bandwidth, inherent security, low latency, and license-free operation of optical communications, the program envisions a 10- to 100-fold increase in wireless connectivity across all length scales- from a few meters for indoor to tens of thousands of kilometers in space. The paper outlines key research questions addressed by the program's four work packages: Free-Space Optical Channels, Transmit and Receive Technologies, Free-Space Optical Networking, and System Architecture and Integration. It also presents 16 use cases encompassing terrestrial applications-ranging from short-range indoor scenarios to long-range terrestrial communications-as well as space applications, including scenarios in Low Earth Orbit (LEO), Geostationary Orbit (GEO), and ultra-long-range deep space communications. It also provides information on the program's status via details on the generated research output in the 15 projects. Finally, the paper provides a detailed impact plan, linking the program's direct outputs to broader outcomes that enable the intended impact of the initiative.