What’s FBG and how does an FBG sensor work?
Fiber Bragg Gratings (FBGs) are made by lateral exposure of an optical fiber with a periodic pattern of intense laser light. The generated pattern will be translated into a permanent refractive index change inside the fiber core forming a grating. The resulting FBG acts as a wavelength selective mirror for one distinct wavelength (Bragg wavelength).
By exposing a fiber with several FBGs with broadband light, each grating is reflecting a certain amount of light at a different Bragg wavelength which can be spectrally detected. If the FBG fiber is manipulated by variations of strain and temperature a shift of the Bragg wavelength is measured, which can be used to calculate strain and temperature values very accurately. From the basic functionality of measuring strain and temperature and many other parameters like force, pressure, acceleration, vibration and displacement can be additionally derived.
Optical fiber sensors present undeniable advantages such as high fatigue limits, multiplexing and immunity to electromagnetic interferences. With our variety of high-quality Fiber Bragg Grating sensors, you are able to measure strain, force, temperature, pressure and shape.
General Advantages of FBG Sensors
FBGs are immune to electromagnetic interference (even lightening interference)
FBGs are intrinsically passive (no electrical power required) and therefore can be positioned in high voltage and potentially explosive atmosphere areas.
As FBGs consume no power, there is also no self-heating effect which might be critical when measuring low heat conductive materials.
FBGs can become read out over large distances, without the need of amplification means underway (>20km)
Multiple FBGs (>20) can be monitored in series on one single optical fiber, no return fiber is needed. Special interrogator techniques even allow having more than 1000 FBG sensors on a single fiber.
Due to the nature of the glass, FBGs show good corrosion resistance.