Refractive Index Sensitivity Characteristics at the Dispersion Turning Point of the Single-solid-hole Microfiber-based Modal Interferometer

We demonstrate an ultrasensitive broadband refractometer based on tapered single-solid-hole fiber operating near the dispersion turning point. Compared with SMF-based microfiber, the operation bandwidth of probing wavelength for ultrahigh sensitivities is broadened by 500 nm.