Fiber temperature sensor employed SMP fiber structure and a long period fiber grating based on a Sagnac loop

Abstract

An all-fiber temperature sensor based on a Sagnac loop is demonstrated experimentally. The sensor head comprises single-mode–multimode–polarization-maintaining (SMP) fiber structure and a tilted long period fiber grating. By measuring the peak wavelength shift, the temperature can be determined. Experimentally we have achieved a sensitivity of 1.5nm/°C when the sensor head is reeled into a round with the radius of 10cm.