Highly sensitive temperature sensing based on a birefringent fiber Sagnac loop

Abstract

The usage of a 1 m Polarization Maintaining Fiber (PMF) as a passive sensing element for the experimental demonstration of a highly sensitive all-fiber temperature sensor based on a Sagnac interferometer configuration is presented here. Using a simple interrogation method tracing the wavelength shift of the obtained interference peaks, we were able to detect variations in a water bath temperature with a highly linear response with coefficient of determination (R2) of 0.9999 and a sensitivity of −1.59 nm/°C for the 18–42°C temperature range. This result demonstrates the feasibility of using this all-fiber device as a temperature sensor for many applications that demands very precise and reliable measurements.