Response characteristics of high temperature resistant fiber Bragg grating

The temperature characteristics of high temperature resistant FBG and the ordinary FBG were experimentally investigated. The ordinary FBG becomes black and brittle, and can not be used in practice even though it still has sensing feature, when temperature reaches more than 300℃. The experiment with the high temperature FBG indicates that the high temperature resistant FBG has good linearity from 20℃ to 350℃, and it is not carbonized, the sensitivity is 0.01nm/MPa, but the linearity is deteriorated with the further increase of temperature. The result shows that the high temperature resistant FBG can be used for the high temperature oil downhole measurement.