Distributed temperature fiber Bragg grating sensor

We propose a temperature measurement system based of fiber Bragg grating (FBG). FBG is applied as a sensor element, and a measurand is controlled in the finite number of points. For temperature registration and control of FBG reflection spectrum shift due to applied strain each sensor is tuned to a certain field of measured parameters. Strain response arose due to both to fiber prolongation, and corresponding changes of FBG period, and to changes of fiber properties from photoelasticity effect. Temperature response arose due to inner thermal expansion of fiber material and thermal dependence of refractive index. In present work for separation strain and temperature influence is proposed special sensor construction. Temperature sensor construction protects fiber with FBG from mechanical loads. Construction of reference strain sensor allows to reduce temperature influence at the expense of heat-insulating.