Highly sensitive temperature sensor using nested hollow-core anti-resonant fibers

A highly sensitive temperature sensor based on composite nested negative curvature hollow-core fiber is proposed. Three resonant tubes are nested inside the cladding tubes to induce a resonant coupling between the fundamental core mode and the dielectric mode of the nested resonant tube. Three glass-sheet conjoined nested tubes are introduced to suppress the comparatively low loss higher-order mode LP₀₂. All the air-holes are filled with temperature-sensitive liquid of ethanol. As the temperature changes, the resonant dip in the transmission spectrum corresponding to the coupling will shift. Numerical simulation results indicate that the temperature sensitivity is 3.36 nm °C⁻¹ in the range of 20 °C–40 °C. Since there is no need of any special post-processing, such as selective infiltration or material coating for the sensors proposed, the sensor provides a promising mechanism for the optical fiber temperature sensing.