Experimental study on fibre Bragg grating temperature sensor and its pressure sensitivity

摘要

At present, ocean temperature almost depends on electric signal inspection, but the sensor is not safe in the water. In order to overcome this shortage and improve measurement veracity and safety, the temperature sensing theory of Bragg grating was analysed and a new ocean temperature sensor was presented with advantages of all optic elements, underwater safety and feasibility of sensor network, etc. By setting a spring in the metal tube, the temperature was measured with pressure isolation encapsulation. Multiple plus-minus temperature tests were carried out. Results show that the sensor under the condition of no pressure and the temperature of 0~35°C has an excellent repeatability, hysteresis and linearity. Temperature sensitivity is 29.9 pm/°C, which is close to the theoretical value. Pressure sensitivity tests were executed under the condition of 0~5 MPa. Results show that the wavelength has no change and is not affected by pressure.