Fiber Laser Temperature Sensor based on Sagnac Interferometer

Abstract A fiber laser temperature sensor which is based on Sagnac interferometer is proposed in this work. The fiber laser consists of an erbium-doped fiber amplifier for signal amplification and a Sagnac interferometer for signal filtering. The Sagnac interferometer is made of 30 cm polarization maintaining fiber (PMF) and it acts as the sensing head. Experimental results suggest that the temperature does affect the laser wavelength. As the temperature varies from 30°C to 41°C, the laser wavelength is shifted to the lower wavelength from 1596.5 nm to 1581.8 nm with the recorded sensitivity of 1.1965 nm/°C. The change of the laser wavelength with temperature validates the use of this fiber laser as the temperature sensor.