Bragg grating-based fiber-optic laser probe for temperature sensing

A novel Bragg grating-based fiber-optic laser probe for temperature sensing using erbium-doped fiber as the active gain medium is reported. The combination of a chirped grating and a normal grating was used to form the laser cavity to achieve temperature-tunable laser action over a wide measurement range. The laser probe used a metal sheath to enhance its mechanical strength and contain the normal grating at the sensing point. The temperature dependence of the wavelength of the laser probe gives a sensitivity of 12.01 pm/°C and a repeatability of ±1.7°C from room temperature to 300°C.