FiSens FBG Sensor System

Fiber Bragg Gratings

The Optical Strain Gauge

A fiber Bragg grating (FBG) is a microstructure within the core of an optical fiber comprising a periodic modulation of the refractive index of the underlying glass material. If broadband light guided within the core hits on this periodic microstucture one specific wavelength gets reflected and all other wavelengths of the guided broadband light can pass unhindered.

The periodicity of the FBG defines which specific wavelength gets reflected and is perpetually inscribed into the glass like a spectral finger print. Only if an external force or change in temperature is induced to the microstructure, the periodicity of the FBG will change slightly leading to a specific wavelength shift of the light reflected at the FBG.


FiSens’ fiberoptic sensors measure strains as precise as 1 micrometer per meter and up to a maximum strain of 20.000 µm/m. By easily gluing the fiber onto a surface you can measure deformations along an object.


  • Up to 30 sensors in one single fiber
  • Ultrathin and lightweight
  • Electromagnetic immune
  • Safe in explosive and high radiation environments