Fiber Bragg grating temperature sensor for marine application

Fiber Bragg grating (FBG) sensor for marine exploration has gradually attracted people's attention because of its natural characteristics of low investment and high expansion capability. However, it is well known that FBG is not only sensitive to temperature, but also affected by strain, pressure, vibration, refractive index etc. The cross-sensitivity of FBG results in large measurement error for fiber temperature measurement. As an important error source of optical fiber temperature sensing, strain has attracted much attention of researchers. In order to eliminate the interference of strain on FBG temperature measurement, in this paper, we propose a FBG sensor for ocean applications. Two fiber Bragg gratings with different central wavelengths are cascaded to realize the decoupling of temperature and strain sensing. Experimental results show that the temperature sensitivity of the proposed sensor can reach to 9.49 pm/°C in the range from -5°C to 35°C.