Curvature and strain measurement sensors based on tapered dual-core photonic crystal fibers

This work introduces a novel fiber optic sensor constructed from a tapered dual-core photonic crystal fiber (DC-PCF) configured as a Mach-Zehnder Interferometer (MZI), specifically designed for curvature and strain measurement. The sensor integrates a DC-PCF seamlessly fused to a single-mode fiber (SMF) and incorporates a tapered structure. Experimental results reveal that the waist diameter of the DC-PCF is 61 μm, with a tapered segment length of 4000 μm. The sensor demonstrated remarkable performance, achieving a curvature sensitivity of 6.56 nm/m⁻¹ and a strain sensitivity of -5.59 pm/με. Thanks to its simple design and high reproducibility, this sensor is ideally suited for applications involving axial strain and curvature measurement.