Fiber optic Mach-Zehnder temperature sensor based on dual-core fiber

In this paper, we proposed an in-fiber Mach-Zehnder temperature sensor based on a dual-core fiber (DCF) with one core as the sensing arm suspended in the centre fluidic channel of the DCF and the other core as the reference arm running eccentrically along the fiber. The fluidic channel was infiltrated with silicone oil. Temperature variations would change the refractive index of silicone oil and thus the effective index of the guided mode in the suspended core, thus shifting the interference spectra. The sensitivity of the sensor using a DCF infiltrated with ∼20 cm-long silicone oil was found to be as high as −1.42 nm/°C, comparable to those of the SPR fiber sensors and other interferometric sensors. The measuring range of the sensor was more than 120°C. The proposed sensor could be easily fabricated with good robustness and stability, which makes the sensor suitable for applications such as environment and architecture monitoring.