Microstructural Analysis of Random Hole Optical Fibers

A new type of optical fiber, the random hole optical fiber, has been fabricated and consists of a solid silica central core region surrounded by a porous silica cladding region. The holes present in the cladding region are random in both spatial location and in size, varying from approximately 25 nm to 2.5 microns in radius. Over a thousand holes are present in the fiber. The spectral attenuation in the fiber was measured to be about 2.0 dB/m at 1550 nm. The fibers were prepared by the incorporation of a gas producing agent in the optical fiber preform, which generated the holes in situ during the fiber drawing process.