A method for manufacturing a cubic silicon carbide film includes: a first step of introducing a carbon-containing gas onto a silicon substrate and rapidly heating the silicon substrate to an epitaxial growth temperature of cubic silicon carbide so as to carbonize a surface of the silicon substrate and form a cubic silicon carbide film; and a second step of introducing a carbon-containing gas and a silicon-containing gas onto the cubic silicon carbide film while maintaining the cubic silicon carbide film at the epitaxial growth temperature of cubic silicon carbide, so as to allow further epitaxial growth of the cubic silicon carbide film.

An optical fiber production system includes an annealing furnace having a furnace inlet, a furnace outlet, and a process tube extending between the furnace inlet and the furnace outlet, the process tube having a process tube wall and a heating zone including at least one heating element. The optical fiber production system also includes a gas distribution assembly fluidly coupled to the furnace outlet and structurally configured to induce gas flow from the gas distribution assembly into the process tube such that gas flows within the process tube in an upflow direction.

Systems and methods for drawing high aspect ratio metallic glass-based materials are provided. Methods of drawing a high aspect ratio metallic glass-based material are premised on stably drawing high aspect ratio metallic glass-based material from a preform metallic glass-based composition, accounting for the relationships between: the desired formation of an amorphous structure that is substantially homogenous along the majority of the length of the drawn high aspect ratio material; the desired final geometry of the drawn high aspect ratio material; the nature of the force that is used to draw the molten metallic glass-based composition; the velocity at which the high aspect ratio material is drawn; the viscosity profile of the material along its length as it is being drawn; and/or the effect of temperature on the metallic glass-based material. A precise thermal treatment is imposed along the forming length of the drawn material so as to enable a steady state drawing process, the precise thermal treatment being based on: the desire to develop a substantially same amorphous structure along the length of the drawn material; the desired final geometry for the drawn material; the nature of the force used to draw the material; the velocity at which the material is being drawn; and/or the thermal treatment's impact on the viscosity profile of the material along its length as it is being drawn.

Systems and methods for drawing high aspect ratio metallic glass-based materials are provided. Methods of drawing a high aspect ratio metallic glass-based material are premised on stably drawing high aspect ratio metallic glass-based material from a preform metallic glass-based composition, accounting for the relationships between: the desired formation of an amorphous structure that is substantially homogenous along the majority of the length of the drawn high aspect ratio material; the desired final geometry of the drawn high aspect ratio material; the nature of the force that is used to draw the molten metallic glass-based composition; the velocity at which the high aspect ratio material is drawn; the viscosity profile of the material along its length as it is being drawn; and/or the effect of temperature on the metallic glass-based material. A precise thermal treatment is imposed along the forming length of the drawn material so as to enable a steady state drawing process, the precise thermal treatment being based on: the desire to develop a substantially same amorphous structure along the length of the drawn material; the desired final geometry for the drawn material; the nature of the force used to draw the material; the velocity at which the material is being drawn; and/or the thermal treatment's impact on the viscosity profile of the material along its length as it is being drawn.

A method for manufacturing an optical fiber is disclosed. The method for manufacturing an optical fiber includes: drawing an optical fiber by heating an optical fiber preform inside a drawing furnace into which a first gas is introduced; and annealing the optical fiber by causing the optical fiber to pass through an annealing furnace disposed downstream of the drawing furnace and adjusted to a temperature lower than a temperature at which the optical fiber preform is heated. In the annealing, a second gas having a lower heat conductivity than the first gas is introduced into the annealing furnace through one or more gas introduction ports such that a total flow rate becomes 3 slm or higher, and a flow rate of the second gas per gas introduction port is adjusted to 30 slm or lower.

A method for manufacturing an optical fiber is disclosed. The method for manufacturing an optical fiber includes: drawing an optical fiber by heating an optical fiber preform inside a drawing furnace into which a first gas is introduced; and annealing the optical fiber by causing the optical fiber to pass through an annealing furnace disposed downstream of the drawing furnace and adjusted to a temperature lower than a temperature at which the optical fiber preform is heated. In the annealing, a second gas having a lower heat conductivity than the first gas is introduced into the annealing furnace through one or more gas introduction ports such that a total flow rate becomes 3 slm or higher, and a flow rate of the second gas per gas introduction port is adjusted to 30 slm or lower.

An optical fiber comprises, from a center to a periphery, a fiber core of undoped silica; a cladding layer; and a coating of polyacrylate, wherein the fiber core has a radius of 5 to 7 m and an ellipticity of less than 1.5%, the cladding layer with an ellipticity of less than 0.4% comprises inner, intermediate, and outer cladding layers, the inner cladding layer being doped with fluorine of 5 to 12 m thickness, and refractive index difference to fiber core of 0.4 to 0.2%, the outer cladding layer being undoped quartz of 25 to 45 m thickness, and the coating comprises an inner coating of 25 to 40 m thickness, and an outer coating of 25 to 35 m thickness and an ellipticity of less than 2%. The optical fiber has high durability and large effective transmission area, a method and system for preparing such optical fiber are also disclosed.

An optical fiber comprises, from a center to a periphery, a fiber core of undoped silica; a cladding layer; and a coating of polyacrylate, wherein the fiber core has a radius of 5 to 7 m and an ellipticity of less than 1.5%, the cladding layer with an ellipticity of less than 0.4% comprises inner, intermediate, and outer cladding layers, the inner cladding layer being doped with fluorine of 5 to 12 m thickness, and refractive index difference to fiber core of 0.4 to 0.2%, the outer cladding layer being undoped quartz of 25 to 45 m thickness, and the coating comprises an inner coating of 25 to 40 m thickness, and an outer coating of 25 to 35 m thickness and an ellipticity of less than 2%. The optical fiber has high durability and large effective transmission area, a method and system for preparing such optical fiber are also disclosed.

Disclosed is a preparation method for a GaAs thin film grown on an Si substrate, said method comprising the following steps: (1) Si (111) substrate cleaning; (2) Si (111) substrate preprocessing; (3) Si (111) substrate oxide film removal; (4) first In.sub.xGa.sub.1-xAs buffer layer growth; (5) first In.sub.xGa.sub.1-xAs buffer layer in situ annealing; (6) GaAs buffer layer growth; (7) GaAs buffer layer in situ annealing; (8) second In.sub.xGa.sub.1-xAs buffer layer growth; (9) second In.sub.xGa.sub.1-xAs buffer layer in situ annealing; (10) GaAs epitaxial thin film growth. Also disclosed is a GaAs thin film grown on an Si substrate. The GaAs thin film obtained by the present invention has a good crystal quality, an even surface, and a positive promotional significance with regard to the preparation of semiconductor devices, particularly in the field of solar cells.

An optical fiber comprises, from a center to a periphery, a fiber core of undoped silica; a cladding layer; and a coating of polyacrylate, wherein the fiber core has a radius of 5 to 7 m and an ellipticity of less than 1.5%, the cladding layer with an ellipticity of less than 0.4% comprises inner, intermediate, and outer cladding layers, the inner cladding layer being doped with fluorine of 5 to 12 m thickness, and refractive index difference to fiber core of 0.4 to 0.2%, the outer cladding layer being undoped quartz of 25 to 45 m thickness, and the coating comprises an inner coating of 25 to 40 m thickness, and an outer coating of 25 to 35 m thickness and an ellipticity of less than 2%. The optical fiber has high durability and large effective transmission area, a method and system for preparing such optical fiber are also disclosed.