Theoretical analysis of Sagnac Interferometer based highly sensitive temperature sensor on photonic crystal fiber

In this paper, a highly sensitive temperature sensor is proposed on the platform of photonic crystal fiber (filled with ethanol) and Sagnac interferometer. The sensing characteristics of the device are analyzed by the finite element method. The results show a high temperature sensitivity of 23.23 nm/°C and − 8.71 nm/°C for the fiber length of 24 cm within the temperature range of 45 °C to 60 °C. In addition, the maximum sensitivity of 29.12 nm/°C and − 18.75 nm/°C can be achieved by limiting the temperature range from 43 °C to 50 °C for the same fiber length. Additionally, the effects of structural parameter variation on sensitivity are graphically represented. At last, refractive index (RI) sensitivity, due to the temperature sensitive liquid, is also calculated and obtained average sensitivities are −72,857 nm/RIU and 45,000 nm/RIU as RI varies from 1.3485 to 1.3515. Due to the above promising results, the proposed device may find potential applications in surrounding environmental temperature detection.