Hollow-core photonic crystal fiber based modal interferometer for strain measurement

A modal interferometer based on a 1.2mm hollow-core photonic crystal fiber (HC-PCF) for strain measurement is presented. The modal interferometer is fabricated by splicing the two ends of the HC-PCF to single-mode fibers (SMF). The air-holes in the core and cladding of the HC-PCF are fully collapsed in the splicing process, and the length of each collapsed region is about 300μm. The transmission spectra with different strain levels are measured. The sensitivity of 1.83pm/μɛ is achieved in the range of 0–1260μɛ, and the resolution for strain measurement was about 11μɛ for wavelength demodulation.