Theoretical analysis of a microstructured fiber temperature sensor based on a Sagnac interferometer with a wide temperature measurement range

Abstract

A temperature sensor with a wide measurement range and high sensitivity is proposed and analyzed. It is based on a microstructured fiber (MSF) Sagnac interferometer. The air holes were filled with ethanol by a full filling method. Increase of the birefringence and the sensitivity of the proposed sensor can be achieved by moving the two air holes on the left and right sides of the core. For an MSF with air hole diameters D1 = 0.8 μm, D2 = 0.6 μm, and D3 = 0.4 μm, pitch Λ = 2 μm, and distance R = 8.2 μm, when the length of the MSF is 0.274 cm, the simulation results show that the sensitivity of the proposed sensor can reach 14.7 nm/°C in the temperature range from 15 to 75 °C. This means that the length and sensing range of the MSF have a great influence on the sensitivity of our designed MSF temperature sensor. Because of the advantages of simple structure, high sensitivity, and wide temperature measurement range, the proposed temperature sensor has great application prospects in environmental temperature measurement.