Fabrication of copper oxide–coated hollow waveguides for CO₂ laser radiation

Hollow fibers for transmitting CO₂ laser light were fabricated by the chemical vapor deposition (CVD) method. A dielectric film of copper oxide (Cu₂O) was deposited upon the inside of a Ag-coated glass capillary by use of a metal acetylacetonate as the precursor. The waveguide, which was coated with Cu₂O and had a bore diameter of 700 mm, showed a loss of 0.9 dB/m for CO₂ laser light. The Cu₂O film deposited by CVD had high chemical and heat resistivity. Therefore a hollow fiber coated with copper oxide is suitable for high-power laser applications in a severe environment.