Abstract

In this letter, a high sensitivity fiber optic sensor based on draw tower grating (DTG) is proposed to measure the temperature of seawater. The sensing component is a Fabry-Perot interferometer (FPI) formed by cascading two DTGs with a distance of 50 meters. The temperature signals are demodulated by using the phase measurement method. Experimental results demonstrate that the sensor can achieve temperature measurement in real time and exhibit good linear response to changes in temperature with the sensitivity of 11545 rad/°C. Due to the ultra-weak reflection properties of DTG, the sensing system is expected to achieve quasi-distributed measurement of large-scale seawater temperature, which has some prospects for application in marine engineering.

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