Bell Telephone Laboratories

Detlef Christoph Gloge

Edwin Leroy Chinnock

Herman M Presby

Ivan P Kaminow

Peter W Smith

It has been found that in a profiled optical waveguide for guiding a finite spectrum of light, reduction of total dispersion is possible by forming the overall profile in the waveguide as a composite of at least two profiles of different contour. The profiles contributing to the composite are formed for example through polarizability or density gradations in the waveguide.

Compensation for material dispersion in optical fibers

In accordance with the disclosed invention, a first group of optical fiber waveguides is spliced to a second, similar group of optical fiber waveguides using a unique foldable holder. The holder illustratively comprises a relatively thin wafer formed of a bendable material, such as a plastic or metal, and includes first and second sections disposed about a centrally extended fold line. Each section of the holder includes a plurality of grooves laterally spaced in a parallel relation symmetrically about the fold line for receiving and aligning the individual fibers in each fiber group to be spliced. To achieve the desired splice, the fibers in a first group are placed and then fixed in the grooves of the first section of the holder, while the fibers in a second group are placed and then fixed in the grooves of the second section of the holder. The assembly is then placed in a fiber scoring and breaking tool which divides each of the fibers in the two groups along the same line perpendicular both to the fiber axes and to the holder fold line. The unwanted ends of the fiber groups are then removed from the holder and discarded, and the holder is folded about its fold line bringing the fibers in the first group in accurate alignment with the corresponding fibers of the second group to complete the splice.

Optical fiber group splicing technique and apparatus employing unique

Particular apparatuses implement a method of breaking a rod of brittle material, such as a glass optical fiber, so as to yield a mirrorlike surface across the entire rod end. A decreasing tensile stress is achieved across the cross section of the rod, which at all points is greater than zero but less than the threshold stress at which a mist zone forms, by simultaneously applying longitudinal tension to the rod and bending it in a tool that laterally moves a section of the fiber while holding sections to either side in friction-type clamps. A convenient hand tool for breaking optical fibers uses pivoting clamps which serve to increase tensile stress as bending is increased. Scoring is done before or after the above-mentioned tool operations.

Apparatus for breaking brittle rods or fibers

Graded-index fibers, which are the most promising for first-generation optical communication links, are improved for multimode transmission by employing two or more glassy dopants in the core mutually graded with respect to the silica host and to each other to provide simultaneously minimized intermode dispersion at a first-selected wavelength and, in addition, a broader wavelength range of minimized intermode dispersion, or minimized intermode dispersion at a second distinct wavelength pertinent to the multimode transmission, or optimization of another dispersion-related property of said fiber.

Graded-index fiber for multimode optical communication

Substantial reductions in the distortion loss in an optical fiber waveguide due to the influence of random external forces can be realized by encasing the fiber in a properly designed jacket. In accordance with the disclosed invention, the ability of a jacketed optical fiber structure to resist external forces is characterized by a parameter referred to as its retention length R, given by ##EQU1## WHERE H is the flexural rigidity of the jacketed fiber and D.sub.f is the lateral rigidity of the jacketed fiber. It is shown that minimum distortion loss can be achieved by designing the fiber jacket so that the retention length R of the combined fiber-jacket structure exceeds a critical coupling wavelength .LAMBDA..sub.c for the fiber. A variety of illustrative jacket designs are described.

Optical fiber jacket designs for minimum distortion loss

A method of breaking a rod of brittle material, such as a glass optical fiber, so as to yield a mirrorlike surface across the entire rod end is described. This is achieved by establishing a decreasing tensile stress across the cross section of the rod which, at all points, is greater than zero but less than the threshold stress at which a mist zone forms. This is conveniently achieved by simultaneously applying longitudinal tension to the rod and bending it. A convenient hand tool for breaking optical fibers is also described.

Growing community of inventors

Red Bank, NJ, United States of America

Detlef Christoph Gloge