Free-space optical (FSO) communication systems use laser light to wirelessly transmit data through the atmosphere—or free space—in applications such as telecommunications and computer networking. This new technology is of great interest for developing next-generation communication systems that could help meet the challenges we face in Canada in providing reliable, high-speed connectivity to rural and remote communities. Compared with conventional radio frequency technology, FSO communication systems have the potential to achieve higher data transfer rates using devices that weigh less and consume less power.
To help move FSO technology from concept to market, the High-throughput and Secure Networks Challenge program (HTSN) fostered a collaboration between the National Research Council of Canada (NRC), the University of Ottawa and Canadian company Optiwave Systems Inc. This collaborative effort has given rise to new simulation software that allows technology designers to model and assess the performance of FSO communication systems under development before building prototypes or commercial systems. Using this software, designers can simulate a variety of transmitter and receiver designs, different atmospheric effects such as scintillation, and a range of weather conditions, such as rain, snow, haze and fog—all of which can affect transmission speeds.
Validating an innovative Canadian product
Fibre optics, once a revolutionary innovation using light to transmit information, is now a well-established technology used in cable-based communications networks. But now FSO systems are poised to take these communications networks to a whole new level, with the significant advantage of being able to reach areas where physical cable connections are impossible or impractical. However, because FSO communication systems transmit laser beams through the earth's atmosphere, it can be difficult to predict how air turbulence and weather effects will influence the beams being transmitted, making modelling more challenging. This is where Optiwave's new software comes in.
To help Optiwave validate the ability of its innovative simulation software to make these kinds of predictions accurately, the NRC and the University of Ottawa worked together to develop benchtop and real-world transmitter and receiver stations to put Optiwave's software to the test. These testing stations will also underpin the work in the next iteration of the project, where the focus will shift to laser communication links using high-altitude platforms, uncrewed aerial vehicles (UAV) and faraway satellites. "From that, we can create systems and software models for UAV communications," says Professor Karin Hinzer, University Research Chair in Photonic Devices for Energy at the University of Ottawa.
Those software packages would also be able to model optical power transmission systems, an emerging technology that uses lasers to wirelessly beam energy across distances to power devices such as sensors or drones. A key component of these systems are photonic power converter chips that transform laser light to electrical power and have been used to demonstrate improved power delivery over long distances. "They are unique in the world because they allow power to be transferred at a specific voltage and at very high efficiencies," says Professor Hinzer. "That means users can transform laser power into energy both within the earth's atmosphere and through outer space."
The power conversion chips in this technology are not limited to use in systems that beam lasers between fixed points, but can also be installed on mobile platforms to transmit power to UAVs or drones that may be positioned at different distances.
The research team set up laser links between various targets and a miniature observatory on the roof of an NRC building in Ottawa, Ontario. This 2.5-metre station, named ARTEMIS, was originally designed and built to conduct astronomy research but proved it could be readily adapted for studying laser communications links.
According to Dr. Ross Cheriton, a research officer at the NRC's Quantum and Nanotechnologies Research Centre, the project is a step toward satellite-to-ground communications using lasers. In fact, researchers have already started upgrading ARTEMIS to enable communications with international satellites already in orbit and with new satellites.
"These types of experiments would make it possible to also validate Optiwave's models for longer-range performance across hundreds of kilometres," Dr. Cheriton says. "At the NRC's test facilities, we're also building technology such as new detectors and receivers that can automatically correct for turbulence in free space."
According to Dr. Ahmad Atieh, Vice-President of Optical Systems at Optiwave, the company's free-space optical simulator is a world first. "Optiwave's model is the go-to software for getting the most reliable results because it's already been stress-tested in space and on the ground," he says. While the product was developed for use in Canadian communities, it has sparked much interest in Asia and other parts of the world where providing reliable connectivity to remote areas is a daunting task.
Many hands make light work
Dr. Cheriton notes that the collaborative nature of the project was a clear example of the NRC's signature approach to bringing innovative businesses, scientific expertise, research infrastructure and funding support together to tackle challenges of immediate relevance to Canadian businesses and communities.
"Funding from the High-throughput and Secure Networks Challenge program has fast-tracked this research and development," he says. "It's rare to have a project that provides benefits to technology designers after only months of study, rather than years, because we're bringing the experimental results directly to software design tools."
Dr. Atieh adds that Optiwave's collaboration with renowned experts at the NRC and the University of Ottawa is crucial to building customer trust. "The NRC's validation of the software combined with our ground testing made it possible for us to develop a valuable and reliable tool for researchers, designers and businesses involved in developing free-space optical technologies, a promising pathway towards greater speed and increased reliability of telecommunications in rural and remote areas."
This research was supported by grants and contributions awarded through the Collaborative Science, Technology and Innovation program (CSTIP), administered by the NRC's National Program Office.