What are the fundamental operating properties of fiber optic sensors?
The output signals of fiber Bragg grating sensors are wavelengths of light and are therefore fairly immune from amplitude attenuation. Only wavelengths that fit precisely into the grating pattern will be reflected and measured. If an FBG sensor is strained, its grating period extends proportionally to the strain level, and the wavelength of reflected light also changes proportionally. FBG sensors have the high potential of the strain-measuring principle. As with metal foil gages, the absolute grid lengths of FBG sensors do not affect the measurements, because strain is per definition a relation of two distances (Dl/l0). This is a big advantage over many other measuring principles based on pure displacement measurements. Q: How do FBG sensors benefit measurements for aerospace applications? A: FBG sensors can withstand much higher dynamic strain levels than metal foil strain gages. This is a big advantage when highly stressed carbon- and glass-fiber-reinforced composite structures (such
