Martijn Boerkamp is a science journalist with a strong background in high-tech R&D.

22 June

Aircision and TNO have completed their test of setting up fast data transmission links between two towers using laser beams. They succeeded in 10 Gb/s data transmission over a distance of 2.5 kilometers, which is considered an important landmark for ground-to-ground laser communication. This ‘fiber-optic-through-the-sky’ technology, named free-space optics, can now make its way into 5G broadband connectivity.

With the ever-growing data consumption, technologies can barely keep up with the demand. So far, this growth is supported by microwave antennas, operating in the so-called E-band, or with fiber optics. Both have drawbacks, as the new E-band antennas’ higher frequency prevents them from transmitting farther than one kilometer and only at a maximum of 10 Gb/s. While fiber-optic connections provide fast data transfer over long distances, they’re expensive to place, which limits their implementation to large-scale infrastructures. Free-space optics (FSO), where the information is transmitted via laser beams through the air, solves this: it requires less infrastructure and allows for high data transfer rates.

FSO in itself isn’t new: its origin can be traced as far back as 1880, when Alexander Graham Bell sent information across in the form of light beams, in an invention called the “photophone.” More than 140 years later, the technology still hasn’t taken off, mainly due to the issues concerning atmospheric interference. Clear days provide ideal situations for high-speed data transfer, but any presence of scattering particles in the sky, such as rain, fog or turbulence, can severely impact the transmission. This disqualifies large parts of the world where such weather conditions are the norm, instead of the exception.

Aircision TNO tower
The FSO field test took place between the tower of TNO’s laser communications facility at the Oude Waalsdorperweg in The Hague and the Luchtwachttoren in Scheveningen (photo). Credit: Aircision/TNO

Laser-sharp focus

A special collaboration between Dutch companies and TNO aims to change the field of commercial FSO systems by providing high-speed data transfer links that can cover substantial distances. This commercialization is led by the Eindhoven startup Aircision and is supported by TNO’s expertise and technology within the field of laser communication. In the subsequent steps, the involvement of the Dutch high-tech ecosystem will grow bigger with the interest of VDL ETG, Demcon, as well as KPN to get involved. For TNO, it’s exciting to work with various partners that have the ambition to become a global player, meaning that their technology contributes to making a better tomorrow. But where other partners aim to provide specific components, Aircision aims to develop a complete FSO system and radically change the communication market.

TNO’s Laser Satellite Communication group spent almost a decade developing technology to use laser beams for data transmission, in particular for ground-to-satellite or satellite-to-satellite communication. “Atmospheric conditions also play a role here, as the first layers of the atmosphere can profoundly impact the data transmission,” explains TNO Business Developer for Satellite Communications, Ewa Kadziolka. “But we refined our technology over the years and this knowledge, as well as various technology components, can be applied to spinoff markets, like 5G, or in the future 6G or QKD, as proven in this project.”

Since its start in 2018, Aircision has had a laser-sharp focus on solving the obstacles that have long plagued the FSO market. “Overcoming atmospheric disturbances has been our mission the past few years and each time we’re getting a small step closer,” tells CTO and co-founder John Reid. “The TNO partnership provided us with the tools to make the crucial next step. Luckily, we can also partly rely on the current communication infrastructure, such as transmitters and receivers developed for fiber-optic systems.” But nothing comes for free, as the team had to develop its own technology and IP to make such ground-to-ground FSO links possible.

Alignment in place

To prove their systems were up for the task, over several months, both teams carefully planned a field test. This took place between the tower of TNO’s laser communications facility at the Oude Waalsdorperweg in The Hague and the Luchtwachttoren in Scheveningen. The applied-research organization has been using its facility for several years to test its laser satellite communication systems.

“Keeping the alignment in place is the biggest issue,” says Reid. “The data transfer and receiving systems will never fully stand still. The wind sways them left and right. Rain and fog will add to limiting how much light comes across. And because we’re sending invisible infrared light beams through the air, eye-safe operation is key. Over the years, we’ve built up quite some expertise in this area, which is what we bring to this consortium.”

With the tests, conducted over a distance of 2.5 km, collaborators managed to reach their goal of a wireless link of 10 Gb/s, a benchmark widely acknowledged as the measure for potential use in the 5G infrastructure. Both for Aircision and TNO, this marks an important step. “For TNO, it means we made a significant step in providing our space technology for terrestrial applications,” says Kadziolka. Reid adds: “It’s an important milestone to show we can outperform microwave E-band antennas and provide a realistic solution for the upcoming 5G system.”

Aircision TNO laser eye
With a commercial party, Aircision aims to prove by next year that it’s possible to transmit 20 Gb/s over 5 km. Credit: Aircision/TNO

Record time

“We’re already planning ahead to expand on the data transmission capabilities,” notes Aircision CMO and co-founder Edzard Janssens. “With a commercial party, we aim to prove by next year that we can transmit 20 Gb/s over 5 km. Together, we’ll hit the market by 2022. In 2023, this will lead to a working system capable of 100 Gb/s over 10 kilometers.” The first rollout will be in the Netherlands, which makes sense as the largest part of the consortium is based there. “But we quickly want to expand to other parts of Europe, such as Germany, France, Spain and the UK.”

“For TNO, there’s a lot of value collaborating with the Dutch high-tech industry,” concludes Kadziolka. “We build upon our expertise in designing and developing FSO components together with the FSO instruments consortium and it’s good to see ambitious companies, like Aircision, that want to take the next step, become a service provider and an OEM of the technology. We’ve gained a lot of knowledge over the last seven years in high-precision optomechatronics and compact laser communication terminals that can be reused in ground-to-ground communications.”

“We have the ambition to become the world leader in FSO systems – a market that we’re set to revolutionize,” claims Janssens. “Being in such a strong consortium really makes the difference. With the help of the Dutch high-tech ecosystem, we can develop our technology and roll it out to the market in record time. It’s truly doing business at the speed of light.”