Method and apparatus for introducing geometrical perturbations in optical fiber waveguides
AssigneeBell Telephone Laboratories, Incorporated
InventorHerman Melvin Presby
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Abstract
The present invention relates to method and apparatus for fabricating multimode optical fiber waveguides having reduced modal dispersion as a result of deliberate enhancement of mode coupling in the waveguide. The axial alignment and/or the diameter of an optical fiber waveguide is varied by means of one or more modulated heat sources, such as, for example, a microflame jet or CO.sub.2 laser, directed against the fiber waveguide. By controlling the modulation of the heat source, the spatial distribution of the geometrical perturbation pattern can be controlled, thereby producing controlled mode coupling in the fiber waveguide.
Claims9
A method of introducing controlled geometrical perturbations along a conventional optical fiber waveguide comprising the steps of:
- advancing the optical fiber waveguide through the energy emanating from a heat source, while simultaneously
- modulating the intensity of the energy from the heat source in a predetermined sequence and in a relationship to the speed at which said optical fiber is being advanced through said energy to concurrently heat the optical fiber waveguide to at least within its working temperature and deform the fiber waveguide with the energy from the heat source to yield the desired controlled geometrical perturbation pattern along the waveguide.
Apparatus for introducing controlled geometrical perturbations comprising changes in the direction of the axis and/or the cross-sectional dimensions along a conventional optical fiber waveguide, which comprises
- means for advancing the fiber waveguide through the energy emanating from a source of heat;
- and
- means for modulating the intensity of the energy from said source of heat in a predetermined sequence and in a relationship to the speed at which said fiber is being advanced through said energy to concurrently soften the fiber waveguide to at least within its working temperature and deform the fiber waveguide with the energy from said source of heat to yield the desired controlled geometrical perturbation pattern along the fiber waveguide.
Dependencies are inferred from the claim text.