Ultrahigh-sensitivity temperature sensor based on resonance coupling in organic-liquids-infiltrated side-hole microstructured optical fibers

Abstract:

In this paper, an-organic-liquid-integrated side-hole microstructured optical fiber sensor is proposed for high-sensitivity temperature measurement. The air holes of side-hole fibers are infiltrated with quinoline-dimethyl-sulfoxide mixture to excite the resonance coupling between two liquid rods and the solid fiber core. The fundamental core mode in the core region can be coupled into the liquid rod modes at specific wavelengths satisfying the phase matching condition, and the temperature-induced refractive index variation of the infiltrated materials would cause the resonance wavelength shift. By monitoring the resonance wavelength shift, high-sensitivity temperature sensing can be achieved. Further simulation results based on the finite element method are in accordance with the experimentally observed resonance shift behavior in response to the environmental temperature change. Experimental results show that the maximum sensitivity of the fabricated sensor reaches -4.88 nm/°C for the measurement range of 26.1 °C to 62 °C. Our proposed temperature sensing scheme possesses several desirable merits such as high sensitivity, compact structure and low cost, which is anticipated to find applications in various industrial as well as civil engineering areas.

Key words:temperature sensor; microstructured optical fiber; resonance coupling; organic liquid