Optical fibers are best known for carrying huge amounts of internet data at high speed.
But scientists are increasingly finding ways to use these tiny strands of glass as sensors.
Now, researchers have developed an unusual ribbon-shaped optical fiber that can detect pressure with up to 1,000 times greater sensitivity than conventional designs.
The technology could eventually be used to monitor everything from aircraft and bridges to batteries and medical devices.
Researchers from KTH Royal Institute of Technology in Sweden and the University of Southampton in the UK developed the new flat silica fiber.
Their findings, published in Nature Communications, show that changing the basic shape of an optical fiber can dramatically change how it responds to its surroundings.
Most optical fibers are round. Engineers can flatten conventional fibers afterward, but the researchers took a different approach. They designed and manufactured the fiber in a flat, ribbon-like shape from the beginning.
They also used laser-based glass processing to create carefully controlled structures inside the fiber. These can include tiny air channels or sections filled with metal. By changing these internal features, scientists can customize the fiber to respond to pressure, temperature and potentially other physical changes.
In laboratory experiments, the flat fiber demonstrated pressure sensitivity as much as 1,000 times higher than standard circular optical fibers. The researchers also created a version with improved temperature sensitivity by filling part of its internal structure with a tin-based alloy.
The key idea is that the shape of the fiber is no longer simply packaging for the light traveling through it. Instead, the geometry becomes an active part of the sensor.
That could open up many practical applications.
Flat optical fibers could, for example, be embedded inside the composite materials used to manufacture aircraft and drones. The fibers could continuously detect changes in pressure or strain, potentially providing early warning of structural problems.
Similar sensors could be incorporated into bridges and other infrastructure to monitor their condition over long periods.
Battery technology is another promising area. Pressure and temperature changes inside a battery can provide early signs that something is going wrong. Highly sensitive optical fibers embedded in or around battery systems could potentially detect these changes before they develop into serious safety problems.
Optical sensors also offer advantages over many electronic alternatives. They are lightweight and compact, can work in harsh environments and are not affected by electromagnetic interference. These properties could make them particularly useful in aerospace, energy systems, biomedical technology and advanced manufacturing.
The researchers say their work represents more than simply creating an optical fiber with a different shape. It provides a new platform that engineers can customize for specific sensing tasks while remaining compatible with existing optical technologies.
The next challenge will be moving beyond laboratory demonstrations and incorporating the fibers into practical systems.
In the future, the same glass fibers carrying light could become highly sensitive nerves running through aircraft, batteries, bridges and machines—constantly sensing what is happening around them.
