To restrict deterioration of non-circularity in a constricted portion of an optical fiber preform, provided is an optical fiber preform manufacturing method including introducing inert gas along a surface of the optical fiber preform, causing the inert gas to circulate around the optical fiber preform with an axis of the optical fiber preform in a longitudinal direction as a center, and heating the optical fiber preform in an inert gas environment. In this manufacturing method, the inert gas may be introduced in a direction parallel to a tangent line of the optical fiber preform in a plane orthogonal to the axis.

A method of producing a quartz glass optical component is provided. The method includes providing a cylindrical quartz glass body made of core rod glass and cladding glass. The quartz glass body has a square cut first end having a first outer diameter. The method further includes providing a glass handle having a first end and an opposing square cut second end having a second outer diameter which is between 50% and 110% of the first outer diameter; attaching the square cut end of the glass handle to that of the quartz glass body; and using the glass handle to guide the quartz glass body through a draw furnace. A distortion in a clad-to-core ratio proximate the interface of the cylindrical quartz glass body and the glass handle is less than 5%.

A system for drawing optical fiber in microgravity including a sealed housing to prevent infiltration of at least humidity and filled with a dry environment, a preform holder located within the sealed housing to hold preform material, a furnace located within the sealed housing to receive the preform material from the preform holder and to heat the preform material from which the optical fiber is pulled, a feed system to move the preform material from the preform holder to the furnace, a drawing mechanism located within the sealed housing to pull the optical fiber from the preform material within the furnace, a diameter monitor located within the sealed housing to measure a diameter of the optical fiber and a fiber collection mechanism located within the sealed housing to gather and store the optical fiber.

An optical fiber drawing method where a glass base material passes through an opening provided in a drawing furnace from the material side and drawing is performed by suspending and descending the material into the drawing furnace while being sealed by a sealing mechanism provided in the vicinity of the opening, in which a first portion of the sealing mechanism seals a gap between an outer peripheral surface of the material and an inner surface of the opening when drawing starts and a tapered portion of the material starts passing through the first portion, and a second portion is disposed above the first portion before sealing by the first portion becomes ineffective, and then conduction between inside and outside of the drawing furnace is carried out to prevent fluctuation of pressure inside the furnace immediately after disposing the second portion and the conduction is interrupted when the material further descends.

A seal structure for an optical fiber drawing furnace is for plugging a gap between an upper end opening of the fiber furnace, and an optical fiber glass preform wherein a seed rod and a taper portion are present in an upper portion thereof. The seal structure comprises a first cap member engaging the seed rod of the glass preform; a second cap member covering the taper portion of the glass preform and the first cap member; a spacer member disposed between the first and second cap member, supporting the second cap member, adjusting, via a positional adjustment structure, the height position of the second cap member in the axial direction, and causing the lower extremity of the second cap member to be at a position close to the taper portion; and a seal member which seals between the upper end opening and the glass preform and/or second cap member.

A suspension structure of the present embodiment conveys an optical fiber preform into a drawing furnace. A suspension portion formed in a depressed shape or a projected shape or as a hole is formed in a dummy rod connected on an upper side of the optical fiber preform conveyed into the drawing furnace. The suspension structure includes: a joining mechanism configured to cover at least a part of circumference of the dummy rod and include an arm that extends on both sides in a direction perpendicular to a drawing direction and a retention portion that engages with the suspension portion and retains the optical fiber preform; and an engagement mechanism including a gripping portion with which the arm engages and which hangs the optical fiber preform.

A device for connecting a fiber preform including a plurality of elongate holes extending substantially parallel to a longitudinal axis of the fiber preform to a pressure supply system, the device including a first surface to be connected to an end face of the fiber preform where the plurality of elongate holes end, a second surface including at least two ports configured to be in fluid connection with the pressure supply system, and a channel system within the device connecting the plurality of elongate holes at the first surface to the at least two ports, wherein a density of the at least two ports at the second surface is smaller than a density of the plurality of corresponding elongate holes at the first surface.

The fabrication of sleeveless canes utilizes a preform with an array of glass canes in the preform. At least one tube-sleeve encircles the array of glass canes and is secured to the array of glass canes. The array of glass canes is moved into a furnace wherein the array of glass canes is heated. The furnace is maintained at a furnace temperature within the range of 2000° C. to 1700° C. and the array of glass canes is drawn from the furnace. The drawing of the array of glass canes both scales down the glass canes and elongates the glass canes. Maintaining the furnace at a furnace temperature within the range of 2000° C. to 1700° C. assures that the array of glass canes and the glass canes maintain their original shape.

A system for precoating a preform for drawing optical fiber including a diameter sensor to determine a diameter of pulled optical fiber, a cooling system to cool the optical fiber once it is pulled from a furnace, a coating system to apply a coating to the optical fiber once it has cooled and an ultra-violet lamp to cure the coating.

An optical fiber draw furnace system including a muffle, a downfeed handle, and a downfeed handle extension portion. The downfeed handle is moveably disposed within an inner cavity of the muffle. The downfeed handle extension portion is connected to the downfeed handle and moveably disposed within the inner cavity of the muffle. Furthermore, the downfeed handle extension portion forms a first gap between an outer surface of the downfeed handle extension portion and an inner surface of the muffle, the first gap having a length in a range of about 0.001 m to about 0.2 m.