A shaped tube (50,51) for use as a component in the fabrication of an antiresonant hollow core optical fibre, the shaped tube having a side wall with a transverse cross-sectional shape comprising a number of major curved portions (52) alternating with the same number of minor substantially straight portions (54), each curved portion (52) having an inwardly curving shape, and each straight portion (54) being equidistant from a central longitudinal axis of the shaped tube (50,51).

The present invention relates to a method of manufacturing an optical fiber preform for obtaining an optical fiber with low transmission loss. A core preform included in the optical fiber preform comprises three or more core portions, which are each produced by a rod-in-collapse method, and in which both their alkali metal element concentration and chlorine concentration are independently controlled. In two or more manufacturing steps of the manufacturing steps for each of the three or more core portions, an alkali metal element is added. As a result, the mean alkali metal element concentration in the whole core preform is controlled to 7 atomic ppm or more and 70 atomic ppm or less.

The technology of this application relates to the field of communication technologies, and an optical fiber raw material composition, an optical fiber, and an optical fiber product. The optical fiber raw material composition includes components of the following molar percentages: AlF.sub.3 10%-50%, BaF.sub.2 3%-20%, CaF.sub.2 3%-20%, YF.sub.3 1%-15%, SrF.sub.2 3%-20%, MgF.sub.2 3%-20%, and TeO.sub.2 1%-35%. The optical fiber prepared by using the optical fiber raw material composition provided in this disclosure can be used in aspects such as a mid-infrared band transmission optical fiber, an optical fiber amplifier, a fiber laser, and an optical fiber sensor.

An apparatus and related process for producing a high-strength weld between two glass components. Chucks clamp and move respective first ends of the glass components toward each other inside an enclosure, where the second ends are heated, softened, and welded together in a weld zone. The enclosure has layers of stacked quartz glass bricks and allows the weld zone to cool slowly and avoid stress. A propane quartz melting torch directs a flame inside the enclosure and toward the second ends as the glass components move toward each other. The flame softens the second ends and creates substantially smooth polished surfaces in the weld zone having an increased hydroxide content. At least 80% of the weld zone has a hydroxide content greater than about 10 ppm average in a 10 μm depth from the surface and the tensile strength of the weld zone is above about 10 MPa.

The present invention discloses a glass with high refractive index for fiber optic imaging elements with medium-expansion and fabrication method therefor, the glass comprising the following components in percentage by weight: SiO.sub.2 5-9%, Al.sub.2O.sub.3 0-1%, B.sub.2O.sub.3 23-28%, CaO 0-3%, BaO 6-12%, La.sub.2O.sub.3 30-34%, Nb.sub.2O.sub.5 4-8%, Ta.sub.2O.sub.5 0-1%, Y.sub.2O.sub.3 0-1%, ZnO 4-9%, TiO.sub.2 4-8%, ZrO.sub.2 4-6%, SnO.sub.2 0-1%. The present invention further provides a fabrication method for the glass with a high refractive index, comprising: putting raw materials quartz sand, aluminum hydroxide, boric acid or boric anhydride, calcium carbonate, barium carbonate or barium nitrate, lanthanum oxide, niobium oxide, tantalum oxide, yttrium oxide, zinc oxide, titanium dioxide, zirconium oxide and stannic oxide, etc. into a platinum crucible according to the requirement of dosing, melting at a high temperature, cooling and fining, leaking and casting to form a glass rod, and then annealing, cooling and chilling the molded glass rod.

An example of an optical fiber includes an attenuating cladding disposed around a first waveguide (e.g., a core) and a waveguide (e.g., a waveguide cladding) disposed around the attenuating cladding. An attenuating cladding may be a doped layer that may be doped with, for example, a dopant comprising metal. A first waveguide and a second waveguide may each transmit light for a distinct sample characterization technique. An example of an optical fiber includes a core, a first intermediate cladding disposed around the core, an attenuating cladding disposed around the first intermediate cladding, an attenuating cladding disposed around the first intermediate cladding, a second intermediate cladding disposed around the attenuating cladding, a waveguide cladding disposed around the second intermediate cladding, and outer cladding disposed around the waveguide cladding, and an outer coating around the outer cladding. An optical fiber may be formed using a rod-in-tube process.

A method for manufacturing a fan-in-fan-out device which does not require processing of a small-diameter hole and improves work efficiency of installation of an optical fiber, includes: arranging a first holding member in a hole of a second holding member, the hole being larger than an outer diameter of the first holding member, and holding a plurality of optical fibers between the first holding member and the second holding member respectively along a plurality of grooves formed on an outer periphery of the first holding member or an inner periphery of the hole of the second holding member; heating and integrally melting the arranged first holding member, the plurality of held optical fibers, and the second holding member in a portion including an axial end portion of the second holding member; and drawing the melted portion.

A method for manufacturing an optical fiber preform made of silica-based glass, the method including: forming a core portion; and forming a cladding portion surrounding the core portion, the cladding portion having a refractive index lower than a refractive index of the core portion, wherein the forming the core portion includes: adding an alkali element group consisting of an alkali metal element and an alkaline earth metal element to an inner surface of a glass pipe made of silica-based glass; and integrating the glass pipe and a glass rod disposed inside the glass pipe to form an integrated rod after the adding.

An optical preform manufacturing process is disclosed in which an alkali dopant is deposited between an optical fiber core rod and an optical fiber cladding jacket. Depositing the alkali dopant between the core rod and the cladding jacket permits diffusion of the alkali dopants into the core during fiber draw when the core and the cladding are at their respective transition (or vitrification) temperatures. Introduction of the alkali dopants between the core rod and the cladding jacket also permits decoupling of the alkali doping process from one or more of other optical preform manufacturing processes. The optical preform manufacturing process can also include placing alkali dopants between an optical fiber inner cladding jacket and an optical fiber outer cladding jacket to reduce the glass viscosity during fiber draw.

A method for manufacturing an optical fiber preform includes generating glass particles from a glass raw material gas in a flame obtained by combustion of a combustible gas supplied to a burner and depositing the glass particles on an outer circumference of a silica glass pipe to form a hollow porous glass preform, inserting a rod into the silica glass pipe, transparently vitrifying the porous glass preform by heating the porous glass preform after inserting the rod to obtain a transparent glass preform, drawing out the rod from the silica glass pipe after the porous glass preform is transparently vitrified, and removing the silica glass pipe from the transparent glass preform by etching after drawing out the rod.