The fiber-optic ice detection system from fos4X GmbH has received Germanischer Lloyd certification. The fos4X sensors are based on fiber Bragg grating technology.
This technology uses optical fibers with inscribed optical interference filters. The sensors determine temperature and strain based on the changing reflected wavelength. An approximately cigarette pack-sized spring-mass system detects accelerations and converts them into a displacement that is measured by means of the optical fiber mounted on the deflected mass. The optical signal conductors connected to one or more sensors measuring only three millimetres can be integrated into the fiber-composite materials used to build rotor blades. As opposed to electrical and metallic sensors, fos4X sensors are also not affected by lightning. The ice detection system can be installed by the wind turbine or rotor blade manufacturers ex works, but can alternatively also be bonded and thus retrofitted.