As a new-type sensing element, fiber grating has gained abroad attention from its appearance and achieved
high-speed development in the last 20 years. With the development of fiber grating technology, study on the application
of Fiber Bragg Grating (FBG) sensor has got more recognition.
In this paper the fiber grating sensing system consists of four parts: light-source, fiber grating sensor, demodulation
circuit and signal process circuit. The properties of FBG, the demodulation technology of the sensor, and the network
technology are studied experimentally and theoretically. The following are the main contents:
(1) The sensing characteristics of FBG are analyzed, with the result of a linear relationship between the central
wavelength of FBG and the temperature strain. Meanwhile, the temperature and strain sensing experiment results agree
with the theoretical analysis.
(2) The demodulation method of fiber grating is the key technology of fiber grating sensor. The main demodulation
method includes: filtering method, interference method, tunable light source scanning method. We can use anyone of
them to detect FBG's central wavelength.
(3) The demodulation method based on tunable light source is used, and a fiber grating sensor system based on this
method is developed. Tuning the light source until its output matches the central wavelength of FBG, the peak value will
display, and then the temperature or strain could be known according to this wavelength.