6 minute read
The past, present, and future of optical communications
from Optical Comms
In 1876, Alexander Graham Bell secured his place in history by inventing the telephone. But you know that already. What you might not know is that four years later, he pioneered an idea far ahead of its time: free-space optical communication. Bell’s ‘photophone’ transmitted sound using light. It was ingenious but impractical, hampered by a lack of technology to shield light from environmental interference. Fast forward nearly 150 years, and free space optical communication is no longer an idea confined to the laboratory. It has become one of the most exciting forms of technology in our era and is poised to reshape how we connect in a world that grows more interconnected by the day.
Jean-François Morizur, CEO and co-founder of Cailabs
The foundation for today’s fibre-optic networks was laid in the late 20th century. By the early 2000s, the internet had exploded, demanding data transmission that was both fast and secure. Optical fibres, immune to electromagnetic interference and capable of transmitting data at the speed of light, answered these needs. 100 Gbps networks, coherent optics, and fibre-to-the-home (FTTH) made high-speed, reliable communication commonplace.
But while fibre-optic communication revolutionised terrestrial networks, there is another place where laser is being put to use: space. Satellites, unseen and so very often ignored, play a vital role in modern life – as readers of this title well know – but the world is so connected and digitized that traditional radio frequency (RF) technology is under increasing strain. The RF spectrum, which is finite, is becoming increasingly crowded. Moreover, radio has disadvantages. By dint of propagating in waves, it’s easy to detect, easy to jam, and easy to intercept. During times of relative peace, these shortcomings can be overlooked. However, when conflicts break out, or geopolitical tensions rise – unfortunately, this is where we are now – they become highly relevant.
So why not use laser, not as a replacement for radio, which is a robust, time-honoured technology, despite its flaws, but as a complement? For decades, optical communication faced a challenge, a challenge so great that many thought it intractable. It related to the atmosphere. Laser communication, it almost goes without saying, relies on light. But when light passes through the Earth’s atmosphere, a chaotic medium, its signal gets distorted. The air in the atmosphere isn’t uniform. The temperature varies. The density varies. These variations cause changes in the refractive index, which bends and warps the laser beam.
An analogy: imagine shining a flashlight through water with ripples. The light bends and scatters, creating a blurry and wobbling image. The atmosphere acts, similarly, like a moving, uneven water surface. Only it’s air instead of water. The result is scintillation, beam wander, wavefront distortion. Although laser, due to its intrinsic properties, is very hard to jam, detect or intercept, it was viewed as impractical since you couldn’t retrieve the data it sent from space, which was precisely the point of using it in the first place.
Tough problem to solve
For many years, researchers worked on adaptive optics. It proved a very tough problem to solve. In the early 2010s, while completing my PhD, I was trying to transform light for the purposes of quantum computing. Though I never managed this, I discovered something useful in the attempt: technical results concerning how to split a scrambled laser beam into dozens of smaller, manageable pieces and then reassemble it, restoring the original signal as if it had never been distorted. Telecom giants like KDDI and Bell Labs found this useful for optical fibre communication. But others (in particular, NEC) saw its potential for free-space optical communication and overcoming the problem of atmospheric interference.
The long and short of it is that this technology has now been shown to work. But to make it truly transformative, it must be deployed on an industrial scale. Scaling is not just a technical challenge; insofar as we care about security, the integrity of global communications (undersea cables, one of the main ways we transmit data, are now at constant risk of sabotage) it’s a moral and strategic imperative.
It’s no wonder that global demand for secure, high-speed communication is rising. The threats to traditional systems, from saturation of the RF spectrum to deliberate interference, are growing. There was a time when optical ground stations (OGS), which receive laser signals sent from satellites, were limited to prototypes or academic demonstrations. We’ve moved now from bespoke lab setups to off-the-shelf commercial systems. It’s a game-changer.
Commercial OGSs allow us to achieve economies of scale, making optical communication affordable and accessible. They can be rapidly deployed in a wide range of environments and integrated with other exciting and important forms of technology, like quantum key distribution (QKD), which could lead to unbreakable encryptions.
This is why the future of optical communications is so exciting. Indeed, the implications of industrial-scale optical communication are profound. In the near term, we’ll surely see more secure connections for satellites and unmanned vehicles. Over time, as costs fall and use increases, the technology will touch nearly every sector: from disaster response to financial transactions; from military operations to remote education. Communication will be lightning-fast, over 1,000 times quicker than radio. But crucially, it’ll be secure.
Challenges
The transition will not be without challenges. We need to build an industrial ecosystem around laser communication which requires cooperation across industries, governments, and regulators. We’ll have to ensure that optical communication systems are not just technologically advanced but also interoperable, reliable, and scalable. And we’ll need bold ‘first-movers’, those willing to embrace this evolution and light the way for other, more conservative players.
History shows us that transformative technologies often emerge in the shadows of more established systems. Fibre-optics began as a niche alternative to copper wires; now it’s the backbone of the modern internet. Laser communication, now a mature technology, is poised for a similar leap. It’s an important potential complement to radio and one we should exploit.
We all hope for a world that becomes less and less dangerous. But right now, conditions are febrile. Information is almost as vital to our way of life as air or water and so the fast, secure transmission of data is all-important. The good news is that we have a way of doing it. That’s optical communications, and that’s the future.
For further information contact Cailabs
