Technical Communication Design of Monitoring System of High Temperature Piping System by Heat Resistant Fiber Bragg Grating

Ultrafast laser processing was applied to fabricate fiber Bragg gratings with specific wavelength characteristics. The high-temperature properties were examined. Reflection was not changed greatly when it was exposed to temperature of up to 600°C for 1 hour. A time-domain detector of FBG was produced for vibration measurement. FBG of three wavelength was processed in one optical fiber, and the possibility of the multipoint measurement was shown. It was proposed that the heat-resistant FBG sensors combined with wavelength tunable laser will become powerful tool in surveillance for coolant piping sys-tem in nuclear power plants