Design, fabrication and characterization of integrated antiresonant hollow core waveguides for photonics integrated circuits

We present the design, fabrication and applications of integrated hollow core antiresonant reflecting optical waveguides (ARROWs). Differently from conventional waveguides, in ARROW waveguides the field is not confined in the core region by total internal reflection but by dielectric cladding layers designed to form high reflectivity Fabry-Perot mirrors. This peculiar structure offers some unique properties that make it very attractive for photonics integrated circuits. In particular in these waveguides the core has a refractive index lower than the one of the cladding layers, permitting the realization of hollow waveguides without metal walls. These waveguides can be successfully used in several application fields, ranging from telecommunications to sensors. Here, we report the realization of an integrated optical refractometer based on a simple hollow ARROW waveguide.