High-Q tunable Fano resonances in the curved waveguide resonator with mirrors with spatially variable reflectivity br

High-Q Fano resonances are demonstrated, as well as effects similar to electromagnetically in-duced transparency arising in a curved Fabry-Perot waveguide resonator with variable-reflection mirrors. It is shown that these effects arise as a result of coupling the fundamental mode of the bent waveguide core with whispering gallery cladding modes. An influence of the main geomet-rical parameters of the resonator on the resonance features in its reflection and transmission spec-tra is studied. The results obtained can be used in the creation of new functional elements of pho-tonics based on curved waveguides, in particular, highly sensitive portable refractometers for bio- and chemosensory systems, as well as optical sensors of mechanical effects. Keywords: Fano resonance, electromagnetically induced transparency, bent waveguide, whis-pering gallery mode, optical refractometry