Microporous silica coated silica fibers and methods of manufacture

摘要

Optical 100% silica, low index glass cladding on high purity undoped synthetic or fused silica glass fiber core, can be manufactured by means of sol-gel processing. Sol-gel glass, i.e. a combination of appropriate and compatible silica mixtures derived from silicone fluids and submicron silica glass precursor particulates, is either thermally treated in melt form or applied in dip or spray form and thermally bonded onto the fiber core during the in-line fiberization cycle. Current optical glass fibers containing various dopants can create color centers when exposed to ionizing radiation. These color centers increase optical attenuation in the optical fiber and thus severely degrade performance. Conventional on-line processing of an optical glass fiber waveguide uses dopants to form a high index of refraction silica core using conventional dopants. However, the present inventors' silica sol-gel method offers an inexpensive method of coating to the conformed fiber dimension method for precise clad coating of silica core fiber. The cladding porosity can be tailored for the appropriate index of refraction by controlling the quenching conditions of the sol-gel glass cladding from the liquid state to the submicroscopic amorphous glassy state. A 100% pure silica waveguide overcomes current susceptibility of conventional doped optical glass fiber to nuclear radiation damage.