摘要 |
A method of making an optical fiber, comprising the steps of forming an optical preform having a core and a cladding with different refractive indices, the core being offset from the geometric center of the preform and having a non-circular cross-section defining two transverse orthogonal axes, the core having a longer transverse dimension along one of the orthogonal axes than along the other of the axes for guiding two fundamental modes, which, in combination with the different refractive indices, permits the de-coupling of waves polarized along the axes, the outer surface of the preform having a non-circular cross-section forming an indexing surface with a predetermined geometric relationship to the core and the orthogonal transverse axes so that the location of the core and the orientation of the axes can be ascertained from the geometry of the outer surface, and drawing an optical fiber from the preform with the drawing rate and the temperature of the preform being controlled to produce a fiber with a cross-sectional geometry similar to that of the preform.
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