Europe’s next deep-tech opportunity may be hidden on the seabed. Submarine cables carry communications and electricity between countries, but monitoring the waters around them is technically difficult. A Dutch company is betting that light travelling through optical fibre can become an early-warning system.
Amsterdam-based Optics11 announced €50 million in follow-on equity financing on November 9, bringing investment in the business above €100 million over 15 months.
Existing investors FORWARD.one, Value Creation Capital, SET Ventures and JOIN Capital participated. The funding will expand manufacturing and international operations.
The investment raises a question for European deep-tech founders: can specialised sensing hardware, developed through years of research, become infrastructure that governments and utilities purchase at scale?
Why Europe Is Looking Underwater
In February, the European Commission allocated €347 million under its Connecting Europe Facility digital programme for strategic submarine cable projects, including a €20 million call supporting deployable repair equipment.
According to the Commission, submarine data cables carry 99% of intercontinental internet traffic. Its new security measures address risks including intentional damage and sabotage.
The allocation is not funding awarded to Optics11. Rather, it illustrates a policy priority that could strengthen demand for monitoring technologies.
Repairs become essential after infrastructure is damaged. Sensing technology offers another possibility: identifying suspicious activity or equipment faults before disruption occurs.
How Optical Fibres Can Detect Underwater Activity
Optics11 traces its technology to research at Vrije Universiteit Amsterdam, from which it spun out in 2011.
Instead of relying exclusively on powered electronic sensors at individual detection points, its systems use light to capture minute acoustic disturbances.
The underlying science draws on fibre-optic sensing, including techniques known as distributed acoustic sensing (DAS).
DAS systems transmit laser light through optical fibres and analyse returning scattered light. External vibrations change the optical signal, allowing sections of cable to function as closely spaced sensors.
A 2026 review in Opto-Electronic Advances by Arnaldo Leal-Junior and colleagues examined the technology’s operating principles, configurations, applications and limitations.
The review explained how DAS can exploit existing fibre infrastructure, potentially reducing the need to install separate electronic sensors throughout monitored areas.
Independent field research demonstrates the technology’s capabilities.
In a Scientific Reports study, Aaron Micallef and colleagues tested a portable DAS system using a one-kilometre armoured cable during an eight-day deployment at a depth of 380 metres in Monterey Bay, California.
The system identified all catalogued earthquakes during the deployment and recorded additional seismic and hydroacoustic events.
However, researchers found that signal quality depended strongly on cable geometry and contact with the seabed.
Another 2026 Scientific Reports study by Hamid Shiri and Mohammad Belal examined how buried, exposed and suspended cables respond differently to underwater disturbances.
Their method identified changes in cable-seabed coupling, including along a 5.8-kilometre coastal cable.
These findings establish the potential of underwater fibre sensing while highlighting an engineering limitation: detecting vibrations does not automatically reveal their source.
From University Research to Maritime Security
Optics11 has developed commercial products around different monitoring requirements.
Its OptiBarrier system provides fixed seabed monitoring that the company says can detect and classify underwater targets at distances of up to 100 kilometres from shore.
OptiArray offers mobile sensing through towed arrays. The Dutch Ministry of Defence selected a containerised version for its Anti-Submarine Warfare In A Box programme, intended to expand monitoring capabilities across crewed and uncrewed vessels.
OptiFinder targets electricity infrastructure, using acoustic sensing to detect partial discharges inside high-voltage equipment.
These discharges can indicate developing insulation problems, making early detection relevant to preventive maintenance.
CEO Paul Heiden told Defense News that between five and ten navies were customers, with approximately 35 paid naval trials expected during 2026.
He also acknowledged that Optics11 was not yet profitable and anticipated positive cash flow in 2028.
The distinction between testing, procurement and sustained deployment remains important when assessing its commercial maturity.
The Next Opportunity Is Turning Signals Into Decisions
Other research suggests fibre sensing could extend beyond dedicated surveillance installations.
A 2026 Communications Engineering study by Rong Tang and colleagues demonstrated simultaneous communication and intrusion sensing across 25.45 kilometres of optical fibre, achieving sub-metre localisation in terrestrial experiments.
The findings suggest existing communications networks could potentially acquire additional monitoring functions, although the experiment was not an underwater defence deployment.
Meanwhile, a Discover Artificial Intelligence study by Jinyao Liu and colleagues combined vessel-tracking information, cable topology and underwater acoustic measurements to identify potential threats, including situations involving manipulated tracking data.
Such research highlights an emerging commercial challenge: processing sensor information into reliable warnings rather than simply collecting more data.
For European founders, the opportunity therefore extends beyond manufacturing optical hardware. Value may emerge from signal-processing software, resilient equipment and systems capable of interpreting complex underwater environments.
Optics11’s financing indicates investor confidence in that opportunity. Its next challenge is demonstrating whether European research can support dependable, commercially sustainable deployments across maritime security and energy infrastructure.
