Methods of making optical fiber and products produced thereby.

摘要

An improved multimode optical fiber having substantially higher bandwidth and lower loss is made by varying the volume of the silica which is deposited in passes of a torch assembly (41) along a substrate tube (31) to form a preform tube which is collapsed to provide a preform (80) from which the optical fiber is drawn. As a result, the thicknesses of the outermost deposited glassy layers in the preform tube are greater and those of the innermost layers are less than those of layers in a preform tube made by prior art MCVD processes. This causes the difference in the index of refraction across each glassy layer to be reduced thereby enhancing the bandwidth and reducing the loss of the drawn optical fiber over those properties of optical fiber drawn from preforms made by prior art MCVD processes. Inasmuch as the inventive process also allows a higher deposition rate than before, it may be used to produce single-mode optical fiber at lower costs than before achieved.