A method for manufacturing an optical fiber preform includes: producing a core preform including a core portion made of transparent glass and a first cladding layer obtained by adding fluorine to the core portion; and forming, on an outer periphery of the first cladding layer, a second cladding layer made of glass having a refractive index higher than that of the first cladding layer. Further, a refractive index profile is formed in the first cladding layer due to a fluorine concentration profile, the refractive index profile being provided at least near a boundary surface with the second cladding layer and having a profile such that a refractive index difference between a refractive index of the first cladding layer and a refractive index of the second cladding layer decreases in accordance with a reduction in a distance from the boundary surface with the second cladding layer.

The present disclosure provides optical fiber preforms formed from core canes having large core-clad ratio, intermediate core-cladding assemblies, and methods for making the preforms and core cladding assemblies. The preforms are made with capped core canes. The capping material has a coefficient of thermal expansion less than the coefficient of thermal expansion of the core cane and more closely matched to or lower than the coefficient of thermal expansion of the surrounding cladding monolith in a cane-in-soot process. Presence of the cap reduces stresses that arise from differential thermal expansion of the core cane and cladding materials and leads to preforms having low defect concentration and low probability of failure during subsequent thermal processing steps.

A method for making an optical fiber device may include using a three-dimensional (3D) printer to generate a preform body including an optical material. The preform body may have a 3D pattern of voids therein defining a 3D lattice. The method may further include drawing the preform body to form the optical fiber device.

A substrate dividing method includes preparing a substrate that is formed with division start points along streets and that has a protective sheet attached to a surface on one side thereof and rolling a roller on a surface on the other side of the substrate, to attach an expanding tape. Next, suction by a holding table is cancelled, and, in a state in which a slight gap is formed between a holding surface of the holding table and the protective sheet, the roller is brought into contact with the expanding tape and rolled, thereby extending cracks extending from the division start points while causing the substrate to sink into the gap through the protective sheet with the division start points as starting points, and the expanding tape is expanded to widen the chip intervals with the division start points as starting points.

According to one embodiment, a method for thermally treating glass articles may include holding a glass article at a treatment temperature equal to an annealing temperature of the glass article =15° C. for a holding time greater than or equal to 5 minutes. Thereafter, the glass article may be cooled from the treatment temperature through a strain point of the glass article at a first cooling rate CR1 less than 0° C./min and greater than −20° C./min such that a density of the glass article is greater than or equal to 0.003 g/cc after cooling. The glass article is subsequently cooled from below the strain point at a second cooling rate CR.sub.2, wherein |CR.sub.2|>|CR.sub.1|.

Methods for strengthening edges of a laminated glass article comprising a glass core layer positioned between a first glass clad layer and a second glass clad layer are disclosed. The methods may comprise polishing the cut edges of the laminated glass article with a slurry of polishing media applied to the edges of the laminated glass article with brushes. An edge strength of the laminated glass article is greater than or equal to about 400 MPa after polishing.

Laser processing of hard dielectric materials may include cutting a part from a hard dielectric material using a continuous wave laser operating in a quasi-continuous wave (QCW) mode to emit consecutive laser light pulses in a wavelength range of about 1060 nm to 1070 nm. Cutting using a QCW laser may be performed with a lower duty cycle (e.g., between about 1% and 15%) and in an inert gas atmosphere such as nitrogen, argon or helium. Laser processing of hard dielectric materials may further include post-cut processing the cut edges of the part cut from the dielectric material, for example, by beveling and/or polishing the edges to reduce edge defects. The post-cut processing may be performed using a laser beam with different laser parameters than the beam used for cutting, for example, by using a shorter wavelength (e.g., 193 nm excimer laser) and/or a shorter pulse width (e.g., picosecond laser).

The present invention provides a tin alloy bath for a float bath, an apparatus for manufacturing a float glass, a method for manufacturing a float glass that can provide a high quality float glass in which defects due to coagulation and falling of a volatile tin component have been suppressed, and a float glass manufactured using those. The above-mentioned tin alloy bath for a float bath is a molten metal bath to be placed in the float bath for supplying molten glass to a liquid surface of the molten metal bath, thereby forming into a glass ribbon, and includes 1 mass % or more of copper with the remainder being unavoidable impurities and tin.

A glass substrate for a high-frequency device, which contains SiO.sub.2 as a main component, the glass substrate having a total content of alkali metal oxides in the range of 0.001-5% in terms of mole percent on the basis of oxides, the alkali metal oxides having a molar ratio represented by Na.sub.2O/(Na.sub.2O+K.sub.2O) in the range of 0.01-0.99, and the glass substrate having a total content of alkaline earth metal oxides in the range of 0.1-13% in terms of mole percent on the basis of oxides, wherein at least one main surface of the glass substrate has a surface roughness of 1.5 nm or less in terms of arithmetic average roughness Ra, and the glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

A method of manufacturing a porous glass preform includes depositing glass particles on an outer periphery of a target rod while a burner for synthesizing glass particles and the target rod that is rotating are relatively reciprocated, wherein V and r are gradually reduced while a variation in sweeping pitch P [mm] expressed as V/r is caused to be within a range of a central value±10% when a glass particle deposition layer of a portion satisfying a relation 0.5L≦R≦0.8L is synthesized; where a final outer diameter of the manufactured porous glass preform for an optical fiber is L [mm], an outer diameter of a glass particle deposition body in the middle of the manufacture is R [mm], a rotating speed of the target rod is r [rpm], and a relative moving speed between the target rod and the burner is V [mm/min.].