A method of manufacturing a porous glass preform includes depositing glass particles on an outer periphery of a target rod while a burner for synthesizing glass particles and the target rod that is rotating are relatively reciprocated, wherein V and r are gradually reduced while a variation in sweeping pitch P [mm] expressed as V/r is caused to be within a range of a central value±10% when a glass particle deposition layer of a portion satisfying a relation 0.5 L≤R≤0.8 L is synthesized; where a final outer diameter of the manufactured porous glass preform for an optical fiber is L [mm], an outer diameter of a glass particle deposition body in the middle of the manufacture is R [mm], a rotating speed of the target rod is r [rpm], and a relative moving speed between the target rod and the burner is V [mm/min.].

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 fiber optic imaging element includes medium-expansion and a fabrication method including: (1) matching a core glass rod with a cladding glass tube to perform mono fiber drawing; (2) arranging the mono fibers into a mono fiber bundle rod, and then drawing the mono fiber bundle rod into a multi fiber; (3) arranging the multi fiber into a multi fiber bundle rod, and then drawing the multi fiber bundle rod into a multi-multi fiber; (4) cutting the multi-multi fiber, and then arranging the multi-multi fiber into a fiber assembly buddle, then putting the fiber assembly buddle into a mold of heat press fusion process, and performing the heat press fusion process to prepare a block of the fiber optic imaging element with medium-expansion; and (5) edged rounding, cutting and slicing,

Known heating burners for producing a welded joint between components of quartz glass include a burner head in which at least one burner nozzle is formed, a burner-head cooling system for the temperature control of the burner head and a supply line connected to the burner nozzle for a fuel gas. Starting from this, to modify a heating burner in such a way that impurities in the weld seam between quartz-glass components to be connected are largely avoided, it is suggested that the burner head should include a base body of silver or of a silver-based alloy.

A method for manufacturing a preform for a multicore fiber, including stacking (S1) a plurality of core rods and a plurality of silica-based filler rods in a tube; collapsing (S2) the tube around the stack of core rods and silica-based filler rods, forming a collapsed stack; depositing (S3) a layer of silica around the collapsed stack; removing (S4) at least part of the deposited layer of silica. The preferential process for depositing a layer of silica around the collapsed stack and removing at least part of the deposited layer of silica is Advanced Plasma and Vapor Deposition.

An apparatus for optical fiber manufacturing process is provided, including a raw material providing structure, a dopant providing structure, and a preform forming substrate tube. The dopant providing structure is disposed at a downstream side of the raw material providing structure and in communication with the raw material providing structure. The dopant providing structure includes an outer tube, a first inner tube, a first dopant providing container, a second inner tube, and a second dopant providing container. The first inner tube is disposed in the outer tube. The first dopant providing container is disposed in the first inner tube. The second inner tube is disposed in the outer tube at a downstream of the first inner tube. The second dopant providing container is disposed in the second inner tube. The preform forming substrate tube is disposed at a downstream side of the dopant providing structure.

A method for preparing all-solid-state photonic crystal fiber preform by extrusion by aligning the center of the first jacking end of the first jacking rod with the center of the core outlet mold. The adverse effect on this part of extruded core glass by oxygen or other impurities in air during the extrusion out of the core outlets can be avoided. The defects on the core glass surface and the cladding glass surface can be effectively removed, and the purity and quality of the core component in the obtained fiber preform can be improved.

The invention relates to a method for producing glass fibers that laterally emit light and to glass fibers produced according to said method. The problem of providing a method that relies on standard available glass components, thus making possible an economical production method that allows a glass fiber to be produced which emits laterally and, in an optically active manner, spectrally shifts, scatters and/or filters light coupled into the fiber when said light exits through the fiber cladding, is solved in that, first, glass tubes (7) and glass rods (5) of identical chemical composition and identical optical refractive index are selected, then first the glass rod (5) is coated completely or over parts of its outer periphery with a vitrifiable material mixture containing optically active substances, in the liquid phase, and the glass rod (5) coated in such a way with this coating (6) after said coating has been dried or consolidated is brought into the glass tube (7) and both are jointly drawn, under the application of heat, to form a glass fiber in a known way.

In known methods for producing a glass component, a void-containing intermediate product containing doped or non-doped SiO.sub.2 is inserted into a sheath tube composed of glass, which has a longitudinal axis and an inner bore, and is thermally treated therein. In order to subject the intermediate product to a thermal and/or reactive treatment that is reproducible and uniform in its effect from this starting point, it is proposed in one embodiment that into the sheath tube's inner bore a first gas-permeable gas diffuser is inserted which is displaceable along the sheath tube's longitudinal axis and is pressed against the intermediate product during the thermal treatment.

A method of manufacturing an optical fiber, the method including mounting a glass sleeve in a selective etching apparatus. The sleeve comprising one or more axial through-holes, and the etching apparatus comprising a first end cap with a central aperture disposed therethrough, the first end cap being attached to a first surface of the sleeve. The method further including exposing the sleeve to an acid solution such that a first portion of the first surface is exposed to the acid solution and a second portion of the first surface is not exposed to the acid solution. The first portion being adjacent to the central aperture when the sleeve is mounted in the selective etching apparatus, and the second portion being covered by the first end cap when the sleeve is mounted in the selective etching apparatus.