A (FBG) Fiber Bragg Grating interrogator compares the wavelengths of light reflected from gratings that have been photo-etched into an optical fiber. An intense laser of UV light is sent into the optical fiber in a periodic pattern and the reflections from the etched Bragg gratings are then measured with a photodetector. By measuring modulations in the intensity, phase, polarization, wavelength, or transit time of light in the fiber, the sensor can monitor a wide range of conditions. The FBG interrogator can extract a signal (channel) with a particular wavelength to measure strain, temperature, pressure, acoustics, motion, and more.
The Fiber Bragg grating, also known as a Bragg filter, is used as a passive fiber optic sensor that measures the refractive index around a certain wavelength that fulfills the Bragg condition. The optical interrogator is the data acquisition system that reads the Fiber Bragg Grating sensors. The fiber optic sensor system provides highly accurate, high-speed, reliable data output control with a sensing range over 25 kilometers.