An interrogation technique for fiber Bragg grating sensors based on optical time-domain reflectometry

A method for fiber Bragg grating (FBG) interrogation is proposed. The method rests on measuring the light intensity reflected from FBG sensors by means of a standard optical time-domain reflectometer. Multiple FBGs along the fiber optic line are interrogated through time division multiplexing. Specifications of FBGs enabling linear response of the sensors to strain and temperature are determined. The threshold sensitivity to strain is 0.8 · 10 −4 ; the threshold sensitivity to temperature is 5°C.