Polaroid Corporation

Polaroid-corporation-patent Department

Robert J Mansfield

Richard P Tumminelli

Bill C McCollum

There is disclosed a method of finishing or smoothing the surface of an optical start rod through the use of plasma heat in an atmosphere which prevents contamination of the rod by residual water. Also there is disclosed a method of fabricating an optical waveguide wherein the start rod has deposited thereon silica soot and which is subsequently consolidated by a plasma.

Method of employing plasma for finishing start rods

A chemical vapor deposition method which utilizes a rare earth chelate vapor as a source of rare earth ions for producing an optical fiber having a core with a high rare earth content.

Method for fabricating optical fibers having cores with high rare earth

There is disclosed use of a plasma for consolidating and/or dehydrating a glass soot preform. A plasma is struck in a vessel and the preform is inserted thereinto for effecting treatment of the preform.

Method for employing plasma in dehydration and consolidation of preforms

An optical fiber preform is formed by plasma chemical vapor deposition utilizing a plasma torch that includes a chamber into which a plasma starting gas, such as argon, is introduced and converted to a plasma by application of high frequency electromagnetic energy. A suitable entry port is provided in the torch chamber to allow dopant material in solid form to be introduced directly into the plasma for vaporization or ionization. The dopant material passes into a lower temperature region where gaseous silica precursor gases are introduced to undergo reaction in the presence of the vaporized dopant to form appropriately doped silica particles for deposition onto a substrate. Solid dopants of low volitility or vapor pressure may be used as dopants which could not otherwise be used in vapor deposition processes. The absence of hydrogen in the reaction dynamics results in a preform having greatly reduced hydroxyl ion content. If desired, a high-purity starting glass, rather than the precursor gases, can be introduced directly into the plasma to form the appropriately doped material.

Method for forming doped optical preforms

An improved method for forming optical fiber preforms by the chemical vapor deposition technique utilizes an elongated burner having an array of burner orifices that forms an elongated silica particle stream having a thickness generally related to the diameter dimensions of a cylindrical preform starter rod. The burner can be formed as an elongated plate having the array of gas ports that produce the desired or silica stream. As a consequence, high initial silica particle deposition rates are obtained compared to prior methods utilizing circular burners, with the high initial deposition rates maintained throughout preform fabrication to result in an increase in preform production rates with an accompanying reduction in costs.

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Stow, MA, United States of America

Robert J Mansfield