| 摘要 |
Embodiments of the invention include a method for making a multiple overclad optical fiber preform. The method includes positioning a first overclad tube (14) around a preform core rod (12), positioning at least one second overclad tube (56) around the first overclad tube, and collectively heating the preform core and the overclad tubes under pressure to collapse the overclad tubes onto the preform core rod thus producing a multiple overclad optical fiber preform. Heating occurs either in a draw tower furnace, for example, as part of an Overclad During Draw (ODD) process, or, alternatively, by a separate heating source prior to introducing the preform into the draw tower, for example, as in a conventional Rod-In-Tube (RIT) process. The method also includes drawing optical fiber as portions of the preform are being heated in the draw tower furnace or, alternatively, heated by a heating source separate from the draw tower and then moved to the draw tower. <IMAGE> |
