According to TeleGeography, our seas and oceans contain more than 1.3 m km of fibre cables — more than enough to reach the moon and back — span the world’s oceans and seas. Over 97% of global internet traffic is carried by undersea infrastructure. Now, new research reveals how this vital network is being transformed into a powerful tool for monitoring and security. Fibre-optic cables are useful for detecting sabotage because they can function not only as data transmission lines but also as highly sensitive sensors.
Subsea cables as sabotage sensors and environmental monitors
Subsea fibre-optic cables are being repurposed to not just to carry data, but also act as sensors capable of detecting sabotage and environmental disturbances. These cables can detect subtle changes in light polarization. This enables them to monitor seismic activity and underwater conditions with remarkable precision. Existing cables can usually be retrofitted with monitoring systems. While this type of technology has previously been used for earthquake and tsunami detection, advances in signal repeaters and interrogators are now enhancing its sensitivity, allowing it to pick up smaller disturbances. This approach can provide live data on the location and nature of a disturbance and pinpoint events to within a few metres along a cable that’s hundreds or thousands of kilometres long. Current systems can estimate the size, location, and movement of nearby vessels, with the potential to match this data to satellite or AIS (Automatic Identification System) records.
Monitoring critical infrastructure with Prysmian
Prysmian has been actively advancing the use of fibre-optic cables as sensors to detect sabotage and unauthorized intrusions across various critical infrastructures. These efforts centre around Distributed Fibre Optic Sensing (DFOS) technology, which transforms standard fibre-optic cables into real-time monitoring systems capable of detecting environmental and physical disturbances. There are three main types of DFOS: Distributed Acoustic Sensing (DAS) detects vibrations or acoustic signals along the cable. When something disturbs the ground or water near the cable (such as digging, tapping, or movement), it creates tiny vibrations that cause slight changes in the light signal, which are picked up and analysed. Distributed Temperature Sensing (DTS) measures temperature changes along the cable which can indicate equipment interference or physical strain on the cable. Distributed Strain Sensing (DSS) detects stretching, bending, or pressure on the fibre, which can indicate tampering.
Prysmian is going to launch shortly o-SenS a comprehensive family of fibre sensors for different Distributed Fibre Optic Sensing solutions, such as extreme temperature monitoring (from high temperature to cryogenic), structural health monitoring, bending, leak detection, landsides, border intrusion, etc…
In addition to that, Prysmian offers complete monitoring systems as OPGWatch®, utilising existing fibre-optic cables installed on overhead power lines to monitor the correct infrastructure surveillance.
Prysmian also acquired Omnisens SA, a Swiss company renowned for its long-distance fibre-optic sensing solutions, giving birth to EOSS. This acquisition has enhanced Prysmian's ability to monitor critical infrastructures such as power grids, oil and gas pipelines, and transportation networks.