A method of producing an optical fiber preform includes a silica glass body forming step of forming a silica glass body to be at least a portion of a core portion. The method includes an alkali-metal-doped silica glass body forming step of forming an alkali-metal-doped silica glass body doped with an alkali metal around the silica glass body such that the alkali-metal-doped silica glass body contacts the silica glass body. The method further includes a diffusing step of diffusing the alkali metal from the alkali-metal-doped silica glass body to the silica glass body by a heat treatment.

An apparatus for producing large glass preforms with minimal clad to-core waveguide distortion from a glass body having a weight, an outer surface, core rods, and a cladding surrounding and separated from the core rods by a gap. The apparatus includes collars affixed to the top and bottom of the cladding; a spacer upon which the core rods rest; a first unit holding and supporting both the bottom collar and the spacer; a second unit holding and supporting the top collar; and a frame defining a heating zone having a heating element to heat the glass body. The weight of the glass body above and below the molten glass in the heating zone is supported by the first and second units without contacting the outer surface of the glass body.

An apparatus for producing large glass preforms with minimal clad to-core waveguide distortion from a glass body having a weight, an outer surface, core rods, and a cladding surrounding and separated from the core rods by a gap. The apparatus includes collars affixed to the top and bottom of the cladding; a spacer upon which the core rods rest; a first unit holding and supporting both the bottom collar and the spacer; a second unit holding and supporting the top collar; and a frame defining a heating zone having a heating element to heat the glass body. The weight of the glass body above and below the molten glass in the heating zone is supported by the first and second units without contacting the outer surface of the glass body.

An apparatus and related process for producing large glass preforms with minimal clad to-core waveguide distortion from a glass body having a weight, an outer surface, core rods, and a cladding surrounding and separated from the core rods by a gap. The apparatus includes collars affixed to the top and bottom of the cladding; a spacer upon which the core rods rest; a first unit holding and supporting both the bottom collar and the spacer; a second unit holding and supporting the top collar; and a frame defining a heating zone having a heating element to heat the glass body. The weight of the glass body above and below the molten glass in the heating zone is supported by the first and second units without contacting the outer surface of the glass body.

The invention relates to a device, system, and method for forming a core-rod for optical fibers by collapsing a tube comprising deposited layers of silica to form the core-rod. The device comprises an elongate cavity, an elongate cylindrical carbon liner bounding the cavity, the liner connecting to a frame of the device at opposing end portions, a heating element in a heating element space, surrounding the liner, the liner separating the heating element space from the cavity, a ring of a refractory material, fixated to the frame, surrounding a part of a length of the cavity, the liner being provided such that an inner surface portion at a first end portion of the liner mates with a cylindrical outer surface portion of the ring such that the liner can axially move with the first end portion thereof along the outer surface portion of the ring.

A polarization controller comprising: (i) an optical fiber, and (ii) a carrier surrounding the optical fiber, the carrier comprising an off-center through hole with at least one collapsed region, such that the optical fiber is situated within the through hole and contacts the at least one collapsed region of the through hole, and the collapsed region exerts pressure on the optical fiber.

A polarization controller comprising: (i) an optical fiber, and (ii) a carrier surrounding the optical fiber, the carrier comprising an off-center through hole with at least one collapsed region, such that the optical fiber is situated within the through hole and contacts the at least one collapsed region of the through hole, and the collapsed region exerts pressure on the optical fiber.

A manufacturing method includes forming one or more first holes in a cladding rod, inserting a first glass rod into each of the one or more first holes, heating the cladding rod together with the inserted first glass rod to integrate the first glass rod and the cladding rod and to form an intermediate preform, forming one or more second holes in the intermediate preform, inserting a second glass rod into each of the one or more second holes, and heating the intermediate preform together with the inserted second glass rod to integrate the second glass rod and the intermediate preform.

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.

The vacuum-based methods of forming an optical fiber preform include applying a vacuum to a preform assembly. The preform assembly has at least one glass cladding section with one or more axial through holes, with one or more canes respectively residing in the one or more axial through holes. The opposite ends of the at least one glass cladding section are capped to define a substantially sealed internal chamber. A vacuum is applied to the substantially sealed internal chamber to define a vacuum-held preform assembly. The methods also include heating the vacuum-held preform assembly to just above the glass softening point to consolidate the vacuum-held preform to form the cane-based glass preform. An optical fiber is formed by drawing the cane-based glass preform. The same furnace used to consolidate the vacuum-held preform can be used to draw the optical fiber.