| 摘要 |
<p>The apparatus comprises an opaque screen (8), which is placed between a source and the fibre or preform (7) and has an oblique slit (9) which identifies a plane section of the fibre or preform (7), the index profile of which is determined, and an optical system (10, 11) which forms a near-field image of the beam incident on the fibre or preform and a far-field image of the refracted beam, in two perpendicular directions on a photosensitive element (12). The image is scanned line by line by a television camera the photosensitive element (12) makes part of, and the deflection function and hence the refractive-index profile are obtained from the coordinates of the points with maximum brightness by using a computing system.</p> |
