Demonstration of resonant phenomena analogous to Autler-Townes splitting, electromagnetically induced transparency and Fano resonances in a deformed waveguide resonator

In this paper, we demonstrate resonant phenomena analogous to Autler-Townes splitting, electromagnetically induced transparency and Fano resonances in a resonator based on a single-mode optical waveguide with metallized end-faces. The phenomena are shown to result from strong coupling between the fundamental mode of the waveguide core and the cladding whispering gallery mode. The results obtained open new possibilities in the field of building functional photonic elements using cladding modes of bent waveguides and, in particular, fiber optic refractometers for bio- and chemosensing applications.