Loss and modal properties of Ag/AgI hollow glass waveguides

Hollow glass waveguides, composed of Ag/AgI coatings, have been studied at 10.6 µm. The losses for different bore sizes equal the theoretical loss, which for the 700 µm bore guide was about 0.15 dB/m. The losses for the guides increase upon bending, varying linearly with increasing curvature. These hollow guides propagate a single mode when the bore size of the guide is approximately 30λ. In addition, the best single-mode transmission is obtained when the thickness of the glass wall is large. These smaller bores, thick wall hollow guides, can also be used to filter higher order modes from poor quality input laser beams.