A method for producing a glass fine particle deposit is provided, which arranges a glass synthesis burner and a starting rod in a reaction vessel, and relatively reciprocates the starting rod in an axial direction with respect to the glass synthesis burner so that glass fine particles synthesized by the glass synthesis burner are deposited on the starting rod, in which, as a diameter of the glass fine particle deposit increases, while relatively retracting the glass synthesis burner from the glass fine particle deposit, the method shortens a distance between the glass fine particle deposit and the glass synthesis burner at an end of deposition from that at a start of deposition.

According to a fabrication method for fabricating a porous glass base material for optical fiber, the orientation of a clad forming burner used to form the outermost layer of a clad-corresponding portion is changed further upward while glass fine particles are deposited during the period between a first timing and a second timing. At the first timing, the outer diameter of the porous glass base material for optical fiber has not reached a target outer diameter. The second timing is later than the first timing, and either a timing at which the outer diameter of the porous glass base material for optical fiber reaches the target outer diameter for the first time, or a timing prior to this timing.

Provided is a manufacturing apparatus for manufacturing a soot deposition body, including a main burner that deposits glass microparticles on a target rod while moving parallel to a longitudinal direction of the target rod; and a side burner that is positioned outside of a movement range of the main burner in a movement direction of the main burner, and fires an end portion of the soot deposition body formed on the target rod. The side burner includes a plurality of heating burners arranged distanced from each other in a circumferential direction of the target rod. In the manufacturing apparatus described above, the main burner may include a plurality of deposition burners that are arranged distanced from each other in the circumferential direction of the target rod.

A system and process for making a thin, soot particle or glass sheet is provided. The system includes a soot deposition plate having a deposition surface and a glass soot generating device spaced from the deposition surface along a first axis. The glass soot generating device is configured to generate glass soot particles and to deliver the glass soot particles through an outlet and on to the deposition surface in a layer having a thickness of less than 5 mm. At least one of the soot deposition plate and the glass soot generating device is movable to cause relative movement between the deposition surface of the soot deposition plate and the glass soot generating device. A thin soot or sintered soot sheet is also provided. The soot sheet has a variable surface topography that varies along at least two axes.

According to a fabrication method for fabricating a porous glass base material for optical fiber, the orientation of a clad forming burner used to form the outermost layer of a clad-corresponding portion is changed further upward while glass fine particles are deposited during the period between a first timing and a second timing. At the first timing, the outer diameter of the porous glass base material for optical fiber has not reached a target outer diameter. The second timing is later than the first timing, and either a timing at which the outer diameter of the porous glass base material for optical fiber reaches the target outer diameter for the first time, or a timing prior to this timing.

This burner for producing a fine glass particle deposited body is provided with a metallic gas-feed pipe that forms a burner body, and a cover for covering the gas-feed pipe, wherein: the gas-feed pipe and the cover are integrally formed; the gas-feed pipe has connected thereto a piping through which material gas, oxyhydrogen gas, and seal gas are supplied; and the cover covers, in the axial direction of the burner over a prescribed length and in a given constant outer diameter, the gas-feed pipe and a connection part of the piping connected to a lateral surface of the gas-feed pipe.

According to a fabrication method for fabricating a porous glass base material for optical fiber, the orientation of a clad forming burner used to form the outermost layer of a clad-corresponding portion is changed further upward while glass fine particles are deposited during the period between a first timing and a second timing. At the first timing, the outer diameter of the porous glass base material for optical fiber has not reached a target outer diameter. The second timing is later than the first timing, and either a timing at which the outer diameter of the porous glass base material for optical fiber reaches the target outer diameter for the first time, or a timing prior to this timing.

Provided is a manufacturing apparatus for manufacturing a soot deposition body, including a main burner that deposits glass microparticles on a target rod while moving parallel to a longitudinal direction of the target rod; and a side burner that is positioned outside of a movement range of the main burner in a movement direction of the main burner, and fires an end portion of the soot deposition body formed on the target rod. The side burner includes a plurality of heating burners arranged distanced from each other in a circumferential direction of the target rod. In the manufacturing apparatus described above, the main burner may include a plurality of deposition burners that are arranged distanced from each other in the circumferential direction of the target rod.

Described is a process for the production of synthetic fused silica in which the deposition surface is located for a period of at least 50% of the build-up time of the soot body at a burner distance in which the horizontally integrated luminous intensity of the flame of the burner used in the targetless state is still at least of the maximum horizontally integrated luminous intensity of the flame.