Apparatus and method for drawing an optical fiber having reduced and low attenuation loss, and optical fiber produced therefrom

摘要

An apparatus and method for drawing an optical fiber having reduced and low attenuation loss, and good strength are provided. The apparatus comprises a furnace comprising a furnace chamber provided with heating means having heating elements, wherein a preform is suitably suspended in core tube of the furnace so that its tip can be suitably heated to a temperature suitable for drawing a fiber, the top face of furnace chamber is provided with a diffuser having an orifice for pumping inert gas into core tube of furnace chamber so as to maintain positive pressure inside the core tube; an opening suitable for insertion of preform; a felt capable of sealing a gap between said preform and said diffuser so as to avoid entry of atmospheric gases in core tube of furnace chamber and allowing preform with variations in its diameter to enter core tube of furnace chamber; a diffuser plate on its top surface with aims for covering said felt from top and minimizing its contact with the atmospheric gases; characterized in that top end of preform is provided with a tubular member which is an opaque glass tube non-permeable to infrared [IR] radiations generated during heating of preform inside the core tube of furnace chamber and capable of stopping passing of IR radiations therethrough to said felt to avoid local elevation of temperature at joint between handle and optical fiber preform so as to avoid burning of felt provided at diffuser, and hence to avoid formation of gap between said felt and said tube, and creation of cavity in top part of said core tube of said furnace chamber.