Apparatus for manufacturing erbium-doped optical fibers

Abstract

A method of and an apparatus for erbium-doped optical fibers usable as an optical amplifier allowing optical signals to be directly amplified by themselves, which method and apparatus are capable of reducing manufacturing time while increasing productivity. The methods includes the steps of closing one end of a quartz tube deposited with a clad layer and a core layer, injecting a solution containing erbium and other additive elements into the quartz tube, thereby absorbing the solution in the core layer, removing the solution from the quartz tube after a predetermined period of time elapses, clamping the quartz tube to a clamping chuck via a connecting tube which is connected to the quartz tube, opening again the closed end of the quartz tube, injecting a large amount of gas into the quartz tube, heating the connecting tube by the heating source to a predetermined temperature, thereby warming the gas introduced in the quartz tube, rotating the clamping chuck to uniformly heat the quartz tube, thereby slowly drying the solution absorbed in the core layer of the quartz tube, and heating again the quartz tube by the heating source, thereby softening the quartz tube. Thereafter, the quartz tube may be collapsed into a condensed erbium-doped optical fiber preform, or both ends of the quartz tube may be completely sealed to form an erbium-doped optical fiber preform having a hollow cylindrical structure.