Temperature sensing using micro-deformed looped fiber taper

A novel fiber-optic temperature sensor device based on an optical fiber tapered loop with a micro-deformation at the taper waist section to enhance its sensitivity is presented. The taper waist diameter was selected as 10 mm, and the micro-deformation at the taper waist section enables the formation of spectral deep notches with enhanced sensitivity to external disturbances, such as temperature. Three dissimilar looped devices were fabricated to assess the effectiveness of engaging temperature disturbances ranging from 100 °C to 600°C. It was found that a bi-dose function fits better the wavelength-shift response to temperature changes of the enhanced spectral notches as a function of temperature, with greater R2 values, in contrast with a linear fitting. By using a linear fitting for the whole range of temperatures, the results show a range of average linear sensitivity from approximately 7.39 pm/°C to 17.07 pm/°C. With these discoveries, the proposed device can be used as a high-temperature sensor in a wide range, which makes it attractive for practical applications. The encouraging results obtained in this article contribute significantly to the field of fiber optic high-temperature sensors and have a lot of potential to be used in industry and research.