A schematic (left) and photograph (right) of a photonic dew point temperature sensor that works by detecting changes in the refraction of light as water molecules condense onto the device. (Left image ©2015 IEEE; right image ©2016 A*STAR Institute of Microelectronics)
Many machines such as turbines, oil drills, health monitors, and nuclear reactors require internal sensors to monitor physical states such as temperature. Researchers are developing compact silicon photonic sensors that can provide accurate readings without being damaged by the toxic, corrosive, or even explosive conditions within these machines.

Tiny optical temperature sensors split light into two beams, which travel through different materials and are then brought back together. The resulting interference pattern gives information about the light and the surrounding temperature. One of the standout features of the device is that it does not require mirrors, and instead guides light through loops to bring it back to the interference point. It can measure a wide range of temperatures, and was also around 20 times more sensitive to small temperature changes than existing fiber-optic sensors.

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