Researchers develop fiber optic sensor made from sapphire


Researchers at Oxford University have invented a sapphire fibre sensor that can withstand severe temperatures, with the potential to enhance efficiency and reduce emissions in aircraft and power generation.

The thin and temperature resistant material could be used in sensors to enable high temperature measurements in jet engines, enabling tweaks in performance to reduce emissions and improve performance.

The industrially grown sapphire thread is less than half a millimeter thick and can withstand temperatures of over 2000°C (3,630˚F). When light is injected onto one end of the fiber, some is reflected from a point along the thread that has been modified to be sensitive to temperature, known as a Bragg grating. The wavelength of the reflected light is a measure of the temperature at that point.

How It Works

The researchers etched a channel along the length of the thread using femtosecond laser direct writing, so that the light is contained within a tiny cross-section, one-hundredth of a millimeter in diameter. With this approach, they were able to make a sensor reflecting predominantly a single wavelength of light. Sensors that use the sapphire fiber could produce data that would enable engineers to modify engine conditions in-flight, potentially reducing nitrogen oxide emissions and improving overall efficiency.

The sapphire’s resistance to radiation also gives it possible applications in the space and fusion power industries. According to Head of Research at RACE, UK Atomic Energy Authority, “These sapphire optical fibres will have many different potential applications within the extreme environments of a fusion energy powerplant. This technology has the potential to significantly increase the capabilities of future sensor and robotic maintenance systems in this sector, helping UKAEA in its mission to deliver safe, sustainable, low carbon fusion power to the grid.”


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