Temperature insensitive curvature measurement with a core-offset polarization maintaining photonic crystal fiber based interferometer

Abstract A novel temperature insensitive curvature sensor with just one section of polarization maintaining photonic crystal fiber (PMPCF) is presented. Cladding to core re-coupling can be obtained by core-offsetting one splice joint of a single mode fiber (SMF)-PMPCF-SMF structure. When the curvature increases, a corresponding loss of cladding to core re-coupling will occur. By measuring the extinction ratio (ER) variation or wavelength shift of the interference pattern, temperature insensitive curvature measurement can be achieved. Experimental results show that, with the increase of the curvature, the ER decreases sigmoidally, while the wavelength increases linearly, with a high sensitivity of 2.826 nm/cm −1 , within the curvature range of 0.125–0.333 cm −1 .