An optical fiber draw system and method of operating thereof. The method includes positioning a downfeed handle for supporting an optical fiber preform within a furnace such that the downfeed handle is movable within the furnace. The method further includes operating one or more heating elements to thermally heat at least a portion of an upper muffle extension disposed within the furnace, the one or more heating elements being moveable with the downfeed handle.

An optical fiber draw system and method of operating thereof. The method includes positioning a downfeed handle for supporting an optical fiber preform within a furnace such that the downfeed handle is movable within the furnace. The method further includes operating one or more heating elements to thermally heat at least a portion of an upper muffle extension disposed within the furnace, the one or more heating elements being moveable with the downfeed handle.

A drawing furnace for drawing a glass element includes: a furnace body having an upper end and a lower end. The furnace body includes a top annular plate, an A/C induction coil capable of accepting electrical current and producing an oscillating electronic signal, a cylindrical susceptor capable of producing heat output, a cylindrical quartz beaker, an insulating material disposed between the susceptor and the beaker, and a bottom annular plate housing and supporting at least one of the susceptor, the beaker, and the insulating material. wherein the furnace body comprises a central longitudinal axis; A rotational drive system operably connected to the bottom annular plate by an annular rotation gear system rotates the bottom annular plate along with the susceptor, beaker, and/or insulating material at a frequency between 0.01 to 10 Hz. The electrical current and oscillation frequency determine the heat output of the susceptor.

This seal structure of a wire drawing furnace for an optical fiber is for sealing a gap between an upper end opening of the wire drawing furnace for an optical fiber and a glass base material for an optical fiber inserted from the upper end opening into a furnace core tube. This seal structure has: a plurality of blade members circumferentially arranged in contact with a circumferential side surface of the glass base material for an optical fiber; a guide member, provided around the plurality of blade members, for allowing the plurality of blade members to slide linearly toward the circumferential side surface of the glass base material for an optical fiber; and a pushing/pulling action mechanism that causes the blade members to move in the radial direction of the glass base material for an optical fiber. The center of gravity of the plurality of blade members is located behind the tip surface of the guide member.

An optical fiber draw system and method of operating thereof. The method includes positioning a downfeed handle for supporting an optical fiber preform within a furnace such that the downfeed handle is movable within the furnace. The method further includes operating one or more heating elements to thermally heat at least a portion of an upper muffle extension disposed within the furnace, the one or more heating elements being moveable with the downfeed handle.

A method of heating an optical fiber, the method including flowing gas from a common gas channel into one or more gas outlets of a burner, the common gas channel encircling an aperture of the burner. The method further including igniting the gas to form a flame and heating the fiber with the flame as the fiber passes through the aperture. The one or more gas outlets opening into the aperture such that each gas outlet has a gas outlet bore terminating at an inward-facing wall of the burner that defines the aperture. And the gas outlet bore being oriented at an angle .sub.1 defined between the gas outlet bore and the inward-facing wall of the burner, downstream of the gas outlet bore, that is greater than or equal to 10 degrees and less than or equal to 70 degrees.