Thermal performance of a solder-coated optical fiber Bragg grating sensor

Studies of fiber-optic temperature sensors based on the use of fiber intracore Bragg gratings have drawn much attention recently. In the operation of fiber Bragg grating temperature sensors, the temperature-induced Bragg wavelength shift is around 0.01 nm/°C for a 1.3 or 1.5 μm band Bragg grating. In other words, there is a wavelength shift of 0.01 nm in the reflected light as the sensor experiences a temperature change of 1°C. In the paper, we report the higher thermal sensitivity of a Bragg grating sensor embedded in solder, which is more thermal-expansion sensitive compared with fiber glass