Fibre-optic firm Proximion senses its way into defence and high-tech industries

Whisker-thin fibres with inscribed pattern

Are they the Emperor’s new clothes? The whisker-thin fibres that Proximion works with are barely visible to the naked eye when visiting the production line in Kista. Yet customers can’t get enough of them.

Put simply, the company’s work involves inscribing a pattern directly into the glass fibre thread itself. These are known as jitter, or Fiber Bragg Gratings (FBG). This allows light to be filtered and specific wavelengths reflected. The most obvious benefit is that data can travel faster and over greater distances through fibre cables without interference.

Measurement in extreme environments

But the technology also enables precise measurement in the most demanding conditions. The threads act as extraordinarily sensitive sensors. Proximion counts Formula 1 teams, space technology companies, steelworks, aircraft manufacturers and industrial firms among its clients. All of them need to keep close tabs on the slightest changes in pressure or temperature.

“You could say we can measure where no other technology works,” says Johan Pejnefors, after sketching a simplified diagram on the whiteboard in the meeting room.

“On a cable that’s almost as thin as a human hair, we can measure temperature at a hundred points simultaneously. That gives us very high precision.”

One telling example involves a pulp industry client that extracts oil from a mixture of tall oil soap and black liquor in large tanks. Using Proximion’s sensors, they can determine the thickness of the soap layer through precise temperature readings. Another client, a ball bearing manufacturer, embeds the miniature sensor strands to measure load pressure and rotation. Structural integrity in infrastructure can be monitored in the same way. The applications are considerable.

“Looking ahead, Industry 4.0 and increasing AI-driven automation will need more sensors to collect data with the highest possible level of detail,” says Pejnefors.

Built in Kista, shipped to the world

All manufacturing takes place here in Kista, where the company has been based since its founding 25 years ago. Optical fibre cables are bought in on reels, the grating pattern is applied, and the cable is then encased in a protective sheath, tested and shipped out across the world.

“We also carry out installations from time to time, and we sell our software alongside the physical product.”

Proximion grew out of Sweden’s Institute for Optical Research. This was a state-backed photonics lab that was later absorbed into RISE, the country’s national research institute. In 2014, the company was acquired by Hexatronic Group, a global fibre giant with a total of 1,937 employees and a net turnover of 7.3 billion kronor in its most recent financial year. Proximion remains a relatively small subsidiary within that group, with 25 employees and a turnover of 50 million kronor.

Pejnefors is something of a company veteran. He has been part of the journey since 2004. Back then, the focus was largely on research and development. He stepped into the CEO role in 2018.

Why does this kind of advanced photonics exist in Kista specifically?

“Partly because all the infrastructure is already here – cleanrooms, HEPA filters, liquid nitrogen, heating and cooling systems. And partly because of access to expertise. We have seven or eight PhDs in the company. We have close working relationships with both KTH, Sweden’s leading technical university, and RISE, the national research institute, across various collaborations. We sometimes swap hours with other organisations based in the area, which is enormously valuable. We also have clients just a few blocks away.”

What does it mean to have production and development under the same roof?

“It’s hugely important to us. A great deal of our production equipment is developed in-house. R&D and production work very closely together.”

Pejnefors estimates that roughly two thirds of the customer base remains telecoms companies. The remaining third comprise of industrial clients seeking the sensor technology. Lead times, however, can be considerable.

“We have a steelworks in the Netherlands as a client. We began the collaboration in 2014, they placed an order in 2018, and we installed the sensor system in 2021. There are a lot of questions to resolve around certifications, explosion risk and technology readiness.”

Where does sustainability fit into all this?

“Everything is moving towards more efficient processes, lower emissions and predictive maintenance. Take a steelworks as an example. Our sensors can detect cracks early in the slab, which is the semi-finished steel billet. Better quality assurance means less waste and lower emissions. That’s partly why we’ve received funding from Vinnova, Sweden’s innovation agency, for a project analysing cracks in steel production in Oxelösund.”

Where do you see the biggest opportunities ahead?

“Right now we see considerable potential in defence technology, Industry 4.0 and process industries. Fibre-optic transducers combined with sensors and machine learning is going to be big – and nobody else can do what we do.”

From Kista to the edge of reality

Kista is Stockholm’s buzzing deeptech district – a place where research labs, startups and global tech giants collide just fifteen minutes from the city centre. Want to know more about Kista? Read more here.