Optical fiber communications cable

US4723831A · kind A · utility

Assignees

• American Telephone and Telegraph Company, AT&T Bell Laboratories · US
• AT&T Technologies Incorporated · US

Inventors

• Brian Johnson · Boise, US
• William C. Reed · Sarasota, US
• Carla G. Wilson · Conyers, US

Key dates

• Filing date: Dec 2, 1985
• Grant date: Feb 9, 1988
• Expiry date: Dec 2, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B6/4436
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An optical fiber cable includes a first jacket, typically comprising a polyvinyl chloride material, a core member comprising at least one, typically .ltoreq.10, optical fiber(s), and a core wrap loosely surrounding the optical fiber(s). The optical fiber(s) typically is (are) slightly overstuffed. The cable further comprises three non-metallic strength members (or groups of strength members) completely embedded in the first jacket and coupled thereto. In cables containing three strength members, the coupling is typically characterized by a pull-out strength of at least 25, preferably more than 40, lbs/in of strength member. Each strength member comprises a multiplicity of impregnated filaments, preferably borosilicate glass filaments impregnated with a urethane. The preferred cable typically has a circularly symmetric cross section, with the three strength members, each of radius r.sub.s, disposed longitudinally, their axes a distance R from the axis of the first jacket, with R>1.155(r+r.sub.s) where r is the inner radius of the first jacket. In one embodiment of the invention, the voids between the optical fiber(s) and the core wrap is filled with a filling compound, e.g., a fire …