Lucent Technologies Inc.

Bell Telephone Laboratories

Western Electric Company, Inc.

Agere Systems Guardian Corp.

At&t Technologies, Inc.

Clifton Walk Draper

John Milo Poate

Satya P Sharma

The present applicant has discovered that the application of an etch-rate reducing liquid that selectively wets the mask can permit anisotropic wet etching. In a preferred embodiment, the application of a hydrocarbon liquid film to a masked silica surface permits wet etching of straight silica walls without undercutting the mask. It is believed that the oil selectively wets the polymer mask, but not the silica surface. The oil will thus be selectively present at the point where the mask meets the silica. Since the HF etchant does not dissolve the oil, the etching produces straight walls instead of undercutting the mask.

Anisotropic wet etching method

In accordance with the invention, particle contamination in drawing optical fiber is reduced by coating the glass preform with a particle-digesting coating prior to introducing the preform into the induction furnace. At least the end of the preform should be coated and preferably all of the preform. When the preform enters the hot zone, the coating melts and digests refractory particles. The coating material and digested particles dissolve into the silica glass at a low surface concentration that does not substantially change the performance of the drawn fiber. The preferred particle-digesting coating is lithium tetraborate.

Method of making an optical fiber with digestion of retracting particles on the preform

A very thin gold coating (e.g., 270 to 3,500 Angstroms) is vapor deposited on the surface of a nickel substrate. A short radiant energy pulse from a laser having a pulse length of about 130 nanoseconds is directed at the coated surface to melt portions of the gold coating and the nickel substrate therebelow. The energy pulse is removed to permit the melted material to resolidify as an alloy with a high concentration of gold at the surface thereof.

Laser surface alloying

Substrates for use in electrical contacts are prepared prior to plating by rapid surface melting by means of a laser beam or an electron beam. Improved microscopic surface characteristics are obtained. In a preferred embodiment, improved macroscopic surface roughness characteristics are also obtained by shorter-duration melting, typically by means of a pulsed YAG laser. Gold which has been electroplated onto copper alloys prepared by this technique has shown improved resistance to sulfur and chlorine corrosive atmospheres. This allows, for example, a thinner layer of a protective metal to be used to obtain a given degree of protection.

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Hopewell, NJ, United States of America

Clifton Walk Draper