Cascaded anti-resonant reflecting waveguides for simultaneous measurement of temperature and curvature

An optical fiber sensor based on combined anti-resonant reflecting (ARR) mechanism is experimentally demonstrated for simultaneous measurement of temperature and curvature. The sensor head consists of a section of liquid infiltrated simplified hollow core photonic crystal fiber (PCF) spliced to a section of silica capillary. Two types of ARR mechanisms are involved in the sensor structure: the double-layer ARR guidance in the infiltrated PCF, and the single-layer ARR guidance in the silica capillary, which result in two sets of ARR fringes in the transmission spectrum. Due to the difference in the guiding mechanism and waveguide components, the two ARR fringes exhibit different responses to temperature and curvature. By measuring the wavelength shift of the double-layer ARR fringe and the intensity variation of the single-layer ARR fringe, temperature and curvature can be determined simultaneously.