Integrated hollow waveguides with arch-shaped cores

An optical waveguide is described that has a hollow arch-shaped core. Optical confinement for this structure is based on the antiresonant reflecting optical waveguide principle. The waveguides are built on a silicon substrate using a sacrificial etch technique with reflowed photoresist serving as the sacrificial material and producing the core´s arch shape. Investigations of fabrication parameters are reported that allow for predicting a final arch-shaped geometry based on initial photoresist width and thickness. Optical mode guiding is demonstrated in an arch-shaped waveguide with a liquid core.