Temperature-independent curvature sensor based on tapered photonic crystal fiber interferometer

A temperature-independent highly-sensitive curvature sensor by using a tapered-photonic crystal fiber (PCF)-based Mach-Zehnder interferometer (MZI) is proposed and experimentally demonstrated. It is fabricated by sandwiching a tapered-PCF between two standard single mode fibers (SMFs) with the air holes of the PCF in the fusion splicing region being fully collapsed. The tapering of PCF is found to enhance the sensitivity significantly. Large curvature sensitivities of 2.81 dB/m⁻¹ and 8.35 dB/m⁻¹ are achieved in the measurement ranges of 0.36-0.87 m⁻¹ and 0.87-1.34 m⁻¹, respectively, with the resolution of 0.0012 m⁻¹ being guaranteed. The proposed sensor also shows negligible temperature sensitivity less than 0.006 dB/°C.