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 invention relates to exemplary methods, devices, and systems for heating an elongate silica cylinder to form a core-rod for optical fibers. An exemplary heating device includes an elongate cavity, an elongate liner bounding the cavity, a heating element in a heating element space surrounding the liner, the liner separating the heating element space from the cavity, and a gas flushing device for effecting a flow of gas at least through the heating element space. An exemplary method includes providing the elongate silica cylinder such that it extends through the cavity, heating the cylinder locally beyond its softening temperature, and effecting a flow of argon and nitrogen gas during the heating.

There is provided herein a preform for drawing fibres therefrom, the preform formed of east first material and having a non-uniform structure in the longitudinal direction and a method of forming the same.

There is provided herein a preform for drawing fibres therefrom, the preform formed of east first material and having a non-uniform structure in the longitudinal direction and a method of forming the same.

A method may include (1) coating a segment of fiber optic cable with an adhesive substance, (2) forming a coil of the segment of fiber optic cable, (3) deforming the coil into a noncircular shape defining a slot external to the coil while obeying a minimum bend radius requirement for the segment of fiber optic cable, and (4) activating the adhesive substance to stabilize the noncircular shape of the coil. Various other methods and apparatuses, such as those for performing the deforming operation, are also disclosed.

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.

A method for manufacturing a capillary usable as part of a hollow-core photonic crystal fiber. The method includes obtaining a capillary having capillary wall including a first wall thickness; and chemically etching the capillary wall to reduce the wall thickness of the capillary wall. During performance of the etching, a control parameter is locally varied along the length of the capillary, the control parameter relating to reactivity of an etchant used in the etching, so as to control the etched wall thickness of the capillary wall along the capillary length. Also disclosed is a capillary manufactured by such a method and various devices including such a capillary.

A method for forming an optical quality glass is provided. The method includes contacting silica soot particles with a basic additive, forming a silica soot compact, and removing the basic additive from the silica soot compact. A method of forming a cladding portion of an optical fiber preform is also provided.

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.

A method for forming an optical quality glass is provided. The method includes contacting silica soot particles with a basic additive, forming a silica soot compact, and removing the basic additive from the silica soot compact. A method of forming a cladding portion of an optical fiber preform is also provided.