Measuring strains with light

Optical strain gauges (SG), like those in the OptiMet series from HBM, have many advantages compared with conventional SG.

As they are based on Fiber Bragg grating technology - an optical measuring system - where no electrical signal is generated within the optical SG, they are insensitive to electromagnetic interference and can be used without problems under high voltage or in potentially explosive atmospheres, for example.

The installation outlay is also lower in comparison to conventional SG, as a single fiber can contain up to 13 gratings with a distance of 60 cm between each one. At the same time, the fiber is also the transmission medium. The fiber-optic SG in the OptiMet series are available in two versions: Either as the basic fiber (OMF) with Ormocer coating or as a robust variant (PKF), where an additional sheath ensures better protection of the fiber.

While the OptiMet OMF type optical SG are suitable for laboratory applications with a diameter of 195 µm, the more robust OptiMet PKF can be used in numerous different applications concerning experimental stress analysis.