Performance of Submillimeter Square Hollow Waveguides

Author(s): Lytle, Fred E., Bryan G. Splawn

Journal: Appl. Opt. (2002) 41(31): 6660-6665.

Abstract:
Propagation losses are determined for 100 µm x 100 µm square, hollow waveguides constructed from glass capillaries. The small size makes it possible to observe optical effects not easily seen with larger waveguides. The depletion of higher-order even modes creates a large, nonlinear loss. Over a distance of a meter the loss approaches the smaller, linear value expected for the fundamental mode. Additionally, the lowest two even modes beat to produce an oscillatory loss with a period of ~2 cm. Making the focal radius 0.35 the waveguide width minimizes these two effects. In a related study, 50-µm waveguides embossed in polydimethylsiloxane are shown to have losses similar to glass capillaries