Irene B Payne

US Patent:

40212173, May 3, 1977

Filed:

Jul 8, 1975

Appl. No.:

5/594013

Inventors:

Vladimir Edmund Bondybey - Fanwood NJ
Louis Eugene Brus - Madison NJ
Irene Dion Payne - Chatham NJ
Peter Michael Rentzepis - Millington NJ

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

C03B 3702
G01N 2116

US Classification:

65 13

Abstract:

Optical fibers in long line communication links fail often in tensile strength. Analysis of tensile properties reveals a variation in tensile strength with fiber length, pointing to uncommon structural defects randomly occurring along the fiber length. Failures occur from crack propagation at these defects. The defects can be revealed according to the invention by nondestructive monitoring during production via off-plane light scattering. A narrow light beam incident across the fiber diameter is refracted in a pattern characteristic of the fiber geometry. Variations in that pattern are produced by structural variations in the fiber or by surface contamination. The nature of the pattern change can indicate the type of defect.