A reduced diameter optical fibre preform positioned along a longitudinal axis includes a core section defined around the longitudinal axis and a cladding section circumferentially surrounding the core section. The reduced diameter optical fibre preform is manufactured by utilizing a calcium aluminum silicate rod and a fluorine doped glass cylinder.

The present application provides a preparation method for a core-shell structured tungsten/gadolinium oxide functional fiber for X and ? ray protection, comprising: first preparing a core-shell structured tungsten/gadolinium oxide powder; preparing a W@Gd.sub.2O.sub.3/PP blended melt from the powder; and preparing a W@Gd.sub.2O.sub.3/PP composite fiber from the blended melt. The core-shell structured tungsten/gadolinium oxide functional fiber prepared by the method can play a role in synergistic protection in the aspect of radiation protection, eliminate a weak protection area, and effectively absorb secondary radiation generated by radiation. Secondly, the prepared functional fiber has the characteristics of no lead and light weight, and has good application prospects in the aspect of X and ? ray radiation protection.

A molding device and a molding method for an optical fiber preform are provided. The molding device includes a rotating mechanism, an extrusion mechanism, and a cylinder mold that is of a cylindrical structure with two ends each having an opening. After a hollow cladding sleeve is obtained by rotating the cylinder mold through the rotating mechanism, a molten core glass is then reversely extruded into the cladding sleeve in the cylinder mold from bottom to top by the extrusion mechanism to prepare the optical fiber preform.

In a unit gravity environment, a glass preform is encased in a material to generate an encased glass preform. The material remains solid at the glass preform's crystal melting temperature and is inert with respect to the glass preform. The encased glass preform is placed in a microgravity environment and heated to a temperature above the crystal melting temperature until the glass preform melts and is free of crystals, wherein a crystallite-free glass preform is encased within the material. The crystallite-free glass preform is then cooled in the microgravity environment to generate a solid crystallite-free glass preform encased within the material. While still in the microgravity environment, the material encasing the solid crystallite-free glass preform is removed in the microgravity environment and the solid crystallite-free glass preform is polished. A glass optical fiber is then drawn from the solid crystallite-free glass preform in the microgravity environment.

The present application provides a preparation method for a core-shell structured tungsten/gadolinium oxide functional fiber for X and ? ray protection, comprising: first preparing a core-shell structured tungsten/gadolinium oxide powder; preparing a W@Gd.sub.2O.sub.3/PP blended melt from the powder; and preparing a W@Gd.sub.2O.sub.3/PP composite fiber from the blended melt. The core-shell structured tungsten/gadolinium oxide functional fiber prepared by the method can play a role in synergistic protection in the aspect of radiation protection, eliminate a weak protection area, and effectively absorb secondary radiation generated by radiation. Secondly, the prepared functional fiber has the characteristics of no lead and light weight, and has good application prospects in the aspect of X and ? ray radiation protection.

Control apparatus for the formation of a tube (referred to as clad) and subsequent injection of material into the tube (referred to as core) to create a unified product (referred to as preform) while in a microgravity environment. The apparatus permits control of a plurality of key variables during the manufacturing process including heating, cooling, and holding temperature in various parts of the instrument, keeping a precise rotation schedule, maintaining a dry atmosphere, managing any chemical effluent, and ensuring all surfaces are unreactive.

A quantum entanglement device and a method of manufacture thereof are described. Specifically, an optical fiber for generating entangled photons is described that includes an optical core and photon entanglement media disposed relative to the optical core. The photon entanglement media includes at least one non-linear crystal, such as Barium Borate. A method of manufacturing an optical fiber is also described that includes providing a fiber preform that contains a nonlinear optical crystal within it, heating the fiber preform until the fiber preform reaches a predetermined temperature, and drawing the optical fiber form the preform, thereby generating an optical fiber having a photon entanglement media disposed therein, where the photon entanglement media comprises at least one non-linear crystal.

A glass composition for flat cross-section glass fiber includes 50.00 to 60.00% by mass of SiO.sub.2, 9.00 to 18.00% by mass of Al.sub.2O.sub.3, 3.00 to 9.00% by mass of B.sub.2O.sub.3, 15.00 to 30.00% by mass of CaO, 0.10 to 5.00% by mass of MgO, 0.01 to 1.00% by mass of Fe.sub.2O.sub.3, 0.01 to 1.00% by mass of TiO.sub.2, and 0.10 to 2.00% by mass in total of Na.sub.2O and K.sub.2O, in which K.sub.2O/Na.sub.2O is 0.05 or more and less than 0.50, MgO/Fe.sub.2O.sub.3 is 4.10 or more and less than 10.00, and the contents C, M, and T, of CaO, MgO, and TiO.sub.2, and the total content NK of Na.sub.2O and K.sub.2O satisfy the following formula (1). 3.00(CMT/NK).sup.1/23.75 (1)