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).