Demonstration of Heat Resistant Fiber Bragg Grating Sensors Based on Femtosecond Laser Processing for Vibration Monitoring and Temperature Change

Heat resistant FBG sensors were developed by femtosecond laser processing to apply them to high-temperature-operated piping system of nuclear power plants. The FBG sensor was installed on the surface of a steel blade and a vibration test was conducted to detect the resonant vibration frequency of the vibrating blade. The FBG sensor had the heatproof performance at 600 degrees C. A frequency stabilized sensing system using a tunable laser was tested for structural health monitoring in daily operation of nuclear power plants. The FBG sensor was installed on the surface of a steel blade for vibration induced strain measurements. Welding, brazing, soldering and noble metal powder adhesive were discussed for molding the FBG sensors.