FEATURE ENVIRONMENT
Could fibre-optics save you from a tsunami?
Optical fibres are being used to sense environmental events such as temperature, wind speeds or even earthquakes, writes Jessica Rowbury
Fibre sensors are sensitive to temperature, strain, and mechanical perturbations, enabling techniques such as phase interferometry, polarisation interferometry, and Rayleigh, Brillouin and Raman scattering. Optical fibres exist high in the sky, deep
underground, and on the ocean floor, so offer unique opportunities to measure over vast areas where conventional sensing is
often difficult or impossible. Thanks largely to the telecoms industry, the deployment of optical fibres is widespread, but in recent years, the abilities of fibre-optic cables to sense environmental factors have become more apparent. There is currently little overlap between these networks. Recently, efforts have been made to merge their infrastructure to bring cost and coverage benefits to both sectors. “In parallel to optical communications
there is a whole field of fibre sensing. The reason is very simple – the same fibre we love for telecommunications is actually a great sensor,” said Mikael Mazur at Nokia Bell Labs, during a presentation at the recent OFC in San Diego in March. Trying to merge telecom and sensing
networks carries advantages for both. The telecoms industry could increase the reliability of their networks and prevent future outages. And industries could expand their coverage or enable sensing
in areas where it is not yet possible, such as where the cost or deploying cables is prohibitively large. “I’d like to think that this might be a
great opportunity to enable fibre optical communication systems to take a much bigger role in our society than they are today, by not only carrying the data, but also giving us a real-time worldwide roadmap of what goes on,” said Mazur. To accomplish this, Mazur and his team
at Nokia Bell Labs are using transceivers within optical communications networks. “The reason for doing this, and why we find it interesting, is very simple: If we look at the coherent receiver with high-speed digital processing, it’s basically a full-field detector system. So we already have access to a polarisation and phase interferometer… a typical technique used in fibre sensing,” he explained. The team has shown, in a field trial, that a real-time coherent transceiver prototype
Subsea cables could be used to monitor earthquakes in the future 20 Electro Optics May 2023 @electrooptics |
www.electrooptics.com
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