Germanium-coated metal (silver, gold, and copper) hollow waveguides for CO<sub>2</sub> laser energy delivery have been fabricated by electron-beam evaporation and plating techniques in which an acid-soluble glass mandrel with small surface roughness was used. The transmission characteristics of Ge-coated metal hollow waveguides were studied. Ge-coated Ag hollow waveguides showed smaller loss, 0.2 dBm, for CO<sub>2</sub> laser light than Ge-coated Au and Cu waveguides. The transmission characteristics of Ge-coated Ag hollow waveguides were measured in relation to a core diameter and a bending radius.
© 2000 Optical Society of America
Yuichi Komachi, Moriaki Wakaki, and Genichi Kanai, "Fabrication of Hollow Waveguides for CO2 Lasers," Appl. Opt. 39, 1555-1560 (2000)