A glass body manufacturing apparatus includes: a first heating furnace including a furnace core tube accommodating the soot and a first heater, to supply a dehydration gas into the furnace core tube and heat the soot at a first treatment temperature lower than a softening point of the porous portion by the first heater; a second heating furnace including a structural body accommodating the soot and a second heater, to heat the soot at a second treatment temperature equal to or higher than the softening point by the second heater; and a conveyance container, connectable to each of the first and second heating furnaces while keeping airtightness with respect to the atmosphere, to accommodate and hold the soot, and convey the soot between the first and second heating furnaces.

Provided is a member for optical glass manufacturing apparatus. The member is used for optical glass manufacturing apparatus and exposed to a gas containing a halogen element in a high temperature environment of 1100° C. or higher. The member includes dense ceramics containing silicon nitride as a main component, and a porosity of a surface layer of the member is smaller than a porosity of the inside of the member.

Provided is an optical fiber glass preform in which a starting rod and a dummy glass are hardly separated from each other, and a method for manufacturing the glass preform. In the optical fiber glass preform, the dummy glass is fitted into one end of the starting rod, and a part of the dummy glass and the starting rod are surrounded by a clad glass. In the manufacturing method, at the time of connecting the starting rod and the dummy glass, a shape is adjusted in such a manner that an iron is brought into contact with a connection portion and is moved from a starting rod side toward a dummy glass side with appliance of a load.

A system for positioning an optical preform in a furnace is provided that includes an upper muffle and a downfeed handle assembly with a tube defining a first end and a second end, the second end extending into the upper muffle. A handle is disposed within the tube. A second end of the handle extends into the upper muffle and a seal assembly is positioned around both the tube and the handle. The first end of the handle extends through the seal assembly and a drive assembly is coupled with the downfeed handle.

A horizontal lathe for manufacturing a porous optical fiber preform, the horizontal lathe being configured to hold and fix two opposite ends of a target in such a manner that a longitudinal direction of the target is a substantially horizontal direction, and cause the target to be rotated around an axis parallel to the longitudinal direction thereof as a rotation axis. The horizontal lathe includes a thermal expansion absorbing mechanism configured to absorb a change in dimension of the target, the change being due to thermal expansion of the target in a direction of the rotation axis.

A member for optical glass production apparatus is a member exposed to a gas containing a halogen element in a high temperature environment; the member includes a first member (4) directly or indirectly supporting an optical glass (10) and a second member (5) supporting the first member (4).

Provided is an optical fiber glass preform in which a starting rod and a dummy glass are hardly separated from each other, and a method for manufacturing the glass preform. In the optical fiber glass preform, the dummy glass is fitted into one end of the starting rod, and a part of the dummy glass and the starting rod are surrounded by a clad glass. In the manufacturing method, at the time of connecting the starting rod and the dummy glass, a shape is adjusted in such a manner that an iron is brought into contact with a connection portion and is moved from a starting rod side toward a dummy glass side with appliance of a load.

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%.

In a device for producing a large-sized porous base material by a VAD process, the cracking and variation of the outer diameter of the base material are suppressed by forming a smooth tapered part, without changing the length of a non-effective part. In producing the porous base material by a VAD process, the time for a gas to reach a flow amount of the gas in a steady state from starting of the deposition is extended more in a burner that deposits glass microparticles on a layer closer to the outside of the base material.

A deposition system for depositing a chemical vapor onto a workpiece is disclosed, including a deposition chamber having a plurality of components for performing chemical vapor deposition on the workpiece. The workpiece is held by a lathe that rotates the workpiece relative to chemical burners that deposit silica soot on the workpiece. The deposition system has a gas panel for regulating the flow of gases and vapors into the deposition chamber, and a computer for controlling operation of the gas panel and the components in the deposition chamber. Multiple sets of chemical burners are disposed longitudinally along the length of the workpiece. Each set of burners is separated from other sets, such that each set of burners deposit silica particles onto generally different portions of a workpiece. The respective portions include an overlap segment in which one or more burners from one burner set will deposit silica particles on the same portion of the workpiece as one or more burners from another set.