Process for coating optical fibers

US4402993A · kind A · utility

Assignee

• Gulf Eastern Manufacturing Company · US

Inventors

• Sol Aisenberg · Natick, US
• Martin Stein · Bedford, US

Key dates

• Filing date: Mar 20, 1981
• Grant date: Sep 6, 1983
• Expiry date: Mar 20, 2001

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C25/104
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Vitreous optical fibers provided with hermetically sealed coatings applied by method and apparatus comprising; drawing a fiber directly from a fiber extruder into and through an elongated chamber having inert gas air locks at its opposite ends. Between the air locks, the optical fiber passes successively through a series of evacuated chamber sections comprising: first, a plasma-ion milling zone wherein fiber surface contaminants are removed and microscopic surface defects are diminished; second, a carbon film depositing zone wherein elemental carbon, propelled in plasma-ion form, coats the surface of fiber with a diamond-like elemental carbon film of submicron thickness; third, an elemental metal film depositing zone wherein a selected metal such as indium, tin, aluminum or gold is plasma deposited onto the fiber to form a coating of less than micron thickness; and finally a second metal depositing zone wherein a coating, in the order of microns in thickness, of such a selective metal is applied by immersing and passing the fiber through a more condensed molecular form of the metal.