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Three-Dimensional Hollow Optical Waveguide with an Etched Groove Substrate

We present the fabrication and the characterization of a hollow optical waveguide with an etched groove substrate. The propagation characteristics of a slab hollow waveguide were measured. The propagation losses were 1–2 dB/cm and 3–4 dB/cm for TE and TM modes, respectively. We also propose and demonstrate a novel three-dimensional (3D) hollow waveguide with a lateral confinement caused by a step in an etched groove.