Simultaneous measurement of dual-points seawater temperatures using highly-birefringent elliptical-core fibers

Dual-points temperature measurement in seawater is demonstrated based on a seawater temperature sensor assembled by the highly-birefringent elliptical-core fiber (HBECF). The theoretical and experimental transmission spectra of the sensor are studied respectively, which shows good agreement with each other. And a matrix equation is established by analyzing the experiment results, by which the temperature changes can be obtained by measuring the wavelength shifts of spectra. The minimum temperature change that can be detected is 0.016 °C and the measurement error is about 0.1%. The advantages of simple structure, high accuracy, high sensitivity, fast response and anti-electromagnetic interference make the sensor meet the demands of seawater temperature measurement.