Basics of a Fiber Grating Sensor System
The illustration below is intended to assist in the understanding of the parts and operation of one type of fiber optic sensor system.
Covered by multiple US patents
The shown type of system operates as follows:
- The light source emits a broadband spectral pattern with the central wavelength at either 1300 or 1550 nm (as specified by the user)
- The light passes through a beam splitter and then a finite spectra is reflected by the grating sensor where the wavelength is a function of the strain
- The light returns through the first beam splitter, then through a second which separates it into two equal signals
- The signal on one side passes through a optical filter where the spectrum is converted to a linear, amplitude-based signal as it enters the high-speed detector
- The second signal passes directly into the high-speed detector
- The high-speed detector outputs a signal and a reference voltage, respectively.
- Software compares the ratio of the signal to the reference, which yields a number proportional to the strain
