New fabrication technique for random-hole optical fibers

Abstract

A new type of optical fiber waveguide utilizing random holes in the cladding region has recently been fabricated. These random hole optical fibers (RHOFs) rely on holes that are random in both size and spatial location to confine light to the central core region. In this paper, a new technique to fabricate the holes in the cladding region will be presented. The holes are formed in-situ during the fiber drawing process. The new technique reported in this paper utilizes a material, which oxidizes to form a very large amount of “bubbles” at the temperature of the fiber draw. During the fiber drawing process, these bubbles are then drawn out into small diameter tubes within the fiber. By controlling the fabrication conditions, the amount, size, and spatial location of the porosity within the fiber can be controlled. The technique of fabrication and optical as well as SEM micrographs of the resulting structures will be discussed.