Anti-PMD system

Abstract

The invention provides an anti-PMD system comprising: an anti-PMD pulley (1) over which an optical fiber (4) is to roll and which is mounted to rotate about an axis of rotation (ar); and at least two optical fiber guide devices (2, 3) situated on either side of the anti-PMD pulley (1); the axis of rotation (ar) of the anti-PMD pulley (1) being stationary; the only degree of freedom of the anti-PMD pulley (1) being rotation about the axis of rotation (ar) of the anti-PMD pulley (1); and at least one of the guide devices (2, 3) being movable in translation in a translation direction (dt) that is not orthogonal to the axis of rotation (ar) of the anti-PMD pulley (1).

Description

technical field [0001] The present invention relates to the field of anti-PMD systems for reducing the PMD of optical fibers during the fiber drawing process. PMD stands for Polarization Mode Dispersion. Polarization mode dispersion is a disadvantage of optical fibers because it leads to attenuation of signal propagation in the optical fiber. This shortcoming becomes more and more serious with the application of increasing data rates in fiber optic communication networks. Background technique [0002] In a first prior art, it is known to use an anti-PMD system called "SZ system". This system is based on the use of an oscillating rotating pulley. The oscillating pulley is an anti-PMD pulley. Such a system is described, for example, in European patent EP 0 582 405 incorporated herein by reference, or in European patent EP 0 744 636 . The SZ system is located at the bottom of the fiber draw tower, in the plane defined around the bend of the optical fiber through the anti-P...

AI Technical Summary

Problems solved by technology

This third prior art provides sufficient control over the rotation of the optical fiber at moderate fiber pulling speeds, but at the expense of additional disadvantages

These additional disadvantages include a mechanical system that is complex and fragile for wedging the optical fiber when trying not to damage it excessively, and at high fiber drawing speeds, typically 1000 meters per minute ( m / min) above, these problems are about the quality of the coating if the optical fiber is too tightly wedged between the anti-PMD pulleys, or about if the optical fiber is not wedged tightly enough between the anti-PMD pulleys Guidance problem of indirect view optical fiber

The guiding problem results in a reduction in the contact duration between the optical fiber and the anti-PMD pulley, and thus reduces the effectiveness of the rotation of the optical fiber on the anti-PMD pulley, thereby reducing the twisting rotation that the anti-PMD pulley applies to the optical fiber. moment, and thus in the final optical fiber, i.e. in the fiber at the end of the drawn fiber, resulting in too large a PMD value

This type of system, which compresses the optical fiber between two anti-PMD pulleys, handles very poorly the problems associated with changes in the diameter of the optical fiber, because whenever the diameter of the optical fiber changes, the pressure is either too high or too small

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