Method of manufacturing a high mechanical strength optical fiber by drawing under high tension

An optical fiber (F) is pulled by a capstan (6) from a silica preform (1) whose bottom end (20) is softened in an oven (2). After cooling, said fiber is coated with an organic protective coating by means of a coating device (4). According to the invention, the surface of the fiber is reheated under tension by means of a torch (14) upstream from the covering device. Tension stresses in the softened surface layer are therefore relaxed. Cooling, followed by the fiber-drawing tension being removed after the capstan (6) cause said surface layer to be put under permanent compression, thereby reducing the risk of the fiber breaking. The invention is applicable to manufacturing fibers having improved characteristics.