Air Core ARROW Waveguides Fabricated in a Membrane-Covered Trench

We report the design, fabrication, and characterization of hollow-core anti-resonant reflecting optical waveguides (ARROWs) fabricated in a membrane-covered trench. These structures are built on silicon wafers using standard microfabrication techniques, including plasma etching, to form trenches. Four waveguide designs are demonstrated, which have different numbers of thin-film reflecting layers. We demonstrate that optical loss decreases with additional reflecting layers, with measured loss coefficients as low as 1 cm^-1.