An intensity modulated temperature sensor using Ge/P fiber

An all fiber-optic temperature sensor utilizing stable temperature dependence of radiation induced attenuation (RIA) in fiber is proposed. The irradiated fiber after sufficient annealing is used to make sensing head. The test system of temperature sensor is built up to test temperature change of irradiated optical fiber after accelerated annealing at 70°C. The model between temperature and RIA is built up. The characteristics of the temperature sensor are analyzed from several aspects, such as measuring range, sensitivity, linearity and repeatability. The attenuation at 850 nm of irradiated Ge/P fiber after sufficient annealing exhibits monotonic and remarkable temperature dependence in the range from -40°C to 60°C. It can be seen that the temperature behavior of RIA shows wavelength dependence by analyzing the temperature behavior of RIA at 850 nm and 1 310 nm. The temperature sensitivity of Ge/P co-doped fiber at 850 nm is better than that at 1 310 nm. The temperature sensor based on radiation-induced attenuation at 850 nm is feasible. The developed temperature sensor with 18 m irradiated fiber has an average value sensibility of 0.006 8 dB/°C. The maximum absolute error is 1°C, the resolution is 0.15°C, the nonlinearity error is ±3.04%, and the repeatability error is 1.04%.