| 摘要 |
<p>A method of making an optical fiber having an oblong core comprising the steps of depositing layers of core glass particles and cladding glass particles on an enlarged mandrel, removing the mandrel to form a tubular porous preform, consolidating the porous preform to form a dense glass preform, evacuating the central hole of the dense glass preform while stretching that preform to collapse the central hole thereof and form a flattened rod, applying additional cladding material to the rod, and drawing the resultant composite to form an optical fiber. To facilitate the flat collapse of the central hole of the consolidated, dense glass preform and to cause the core to have a large aspect ratio, the inside diameter-to-outside diameter ratio of the dense glass preform should be within the range of 0.3 to 0.9. For preferred core and cladding silica glasses, this ratio should be between 0.5 and 0.6. Also, the mandrel diameter should be at least 12 mm, and it is preferably between 25 mm and 50 mm.</p> |
