Strain and curvature-independent temperature sensor based on an interferometer taper fabricated with a CO2 laser

Abstract

An optical fiber interferometer taper fabricated with a CO2 laser is proposed for strain and curvature-independent temperature measurement. Variations in temperature produce changes in the conditions of the interference between light traveling along the core and cladding and a linear behavior is verified for the relation between the wavelength of the resonant loss peak and temperature, yielding a sensitivity of 110 pm/degrees C for a range between 25 and 510 degrees C. Both the applied strain and curvature only promote significant changes in the transmitted power, leaving the wavelength of the resonant loss peak approximately constant and rendering this optical sensing device a good strain and curvature-independent temperature sensor. (c) 2016 Wiley Periodicals, Inc.