Fabrication of FBG Strain Gauge Used for High Temperature Strain Monitoring

Fiber Bragg Grating (FBG) sensing technology is widely used in detection of temperature, strain and etc. Now the application of FBG sensor is limited below 200°C. Application over 200°C is still an engineering challenge since no suitable FBG strain gauge. In this paper, FBG strain gauge structure which consists of three FBGs is designed and fabricated based on the theoretical strain and stress analysis. This strain gauge can be used for the real-time high temperature strain monitoring situation. The elastic high-temperature alloy (10MoWVNb) is chosen as the substrate. The three FBGs with a similar performance are fabricated on the substrate by high-temperature glue. Among the three FBGs, FBG1 is used for the horizontal strain monitoring, FBG2 is used for the longitudinal strain monitoring, and FGB3 is used for high temperature cross-sensitive compensation. The fabricated high temperature FBG gauge is demonstrated suitable for high temperature strain monitoring by experiment.