A quartz glass crucible 1 having a cylindrical side wall portion 10a, a bottom portion 10b, and a corner portion 10c includes a transparent layer 11 as an innermost layer made of quartz glass, a semi-molten layer 13 as an outermost layer made of raw material silica powder solidified in a semi-molten state, and a bubble layer 12 made of quartz glass interposed therebetween. An infrared transmissivity of the corner portion 10c in a state where the semi-molten layer 13 is removed is 25 to 51%, the infrared transmissivity of the corner portion 10c in the state where the semi-molten layer 13 is removed is lower than an infrared transmissivity of the side wall portion 10a, and the infrared transmissivity of the side wall portion 10a in the state where the semi-molten layer 13 is removed is lower than an infrared transmissivity of the bottom portion 10b.

An optical circuit to be manufactured on a wafer has a problem that characteristics are distributed (biased) in a wafer plane due to various causes in manufacturing. The present invention is characterized in that refractive index distribution of an upper cladding is adjusted on the basis of refractive index distribution of a lower cladding and a core film, a film thickness of the core film, and in-plane distribution such as an execution refractive index of an optical waveguide (calculated from a width of a core pattern).

A quartz glass plate has a quartz glass plate body and a quartz glass member adhered to the quartz glass plate body through an adhesive layer, where the adhesive layer contains silica, and a sum of concentrations of Li, Na, and K ions, being alkali metal ions and Ca ions, being alkaline earth metal ions contained in the adhesive layer is 10 ppm by mass or less. Consequently, a step with a uniform thickness can be formed, and a quartz glass plate is not easily damaged by irradiation with a light containing an ultraviolet ray.

A quartz glass plate has a quartz glass plate body and a quartz glass member adhered to the quartz glass plate body through an adhesive layer, where the adhesive layer contains silica, and a sum of concentrations of Li, Na, and K ions, being alkali metal ions and Ca ions, being alkaline earth metal ions contained in the adhesive layer is 10 ppm by mass or less. Consequently, a step with a uniform thickness can be formed, and a quartz glass plate is not easily damaged by irradiation with a light containing an ultraviolet ray.

This raw material supply device supplies a raw material for producing glass fine particle deposits, to a burner and includes a raw material tank; a liquid raw material pipe having one end thereof connected to the raw material tank; a liquid raw material pressure feed pump that pumps siloxane, being a liquid raw material, from the raw material tank via the liquid raw material pipe; a pressure adjustment valve provided on a secondary side of the liquid raw material pressure feed pump in the liquid raw material pipe; an MFC for liquid, connected to the other end of the liquid raw material pipe; and an aeration device that is connected to the secondary side of the MFC for liquid and aerates the liquid raw material. The pipe on the secondary side of the pressure adjustment valve is connected to a location having lower pressure than the primary side pressure.

This raw material supply device supplies a raw material for producing glass fine particle deposits, to a burner and includes a raw material tank; a liquid raw material pipe having one end thereof connected to the raw material tank; a liquid raw material pressure feed pump that pumps siloxane, being a liquid raw material, from the raw material tank via the liquid raw material pipe; a pressure adjustment valve provided on a secondary side of the liquid raw material pressure feed pump in the liquid raw material pipe; an MFC for liquid, connected to the other end of the liquid raw material pipe; and an aeration device that is connected to the secondary side of the MFC for liquid and aerates the liquid raw material. The pipe on the secondary side of the pressure adjustment valve is connected to a location having lower pressure than the primary side pressure.

A mold for manufacturing a quartz glass crucible by a rotary molding method, having a plurality of grooves that are concentric with respect to a mold rotation axis in at least a straight body portion of an inner surface of the mold, wherein the plurality of concentric grooves are non-penetrating grooves that do not penetrate the mold. This provides a mold for manufacturing a quartz glass crucible by a rotary molding method, having an inner surface made so that it is difficult for quartz powder to slide down when forming a quartz powder compact.

A mold for manufacturing a quartz glass crucible by a rotary molding method, having a plurality of grooves that are concentric with respect to a mold rotation axis in at least a straight body portion of an inner surface of the mold, wherein the plurality of concentric grooves are non-penetrating grooves that do not penetrate the mold. This provides a mold for manufacturing a quartz glass crucible by a rotary molding method, having an inner surface made so that it is difficult for quartz powder to slide down when forming a quartz powder compact.

Disclosed herein are glass-ceramics having crystalline phases including -spodumene ss and either (i) pseudobrookite or (ii) vanadium or vanadium containing compounds so as to be colored and opaque glass-ceramics having coordinates, determined from total reflectancespecular includedmeasurements, in the CIELAB color space of the following ranges: L*=from about 20 to about 45; a*=from about 2 to about +2; and b*=from about 12 to about +1. Such CIELAB color space coordinates can be substantially uniform throughout the glass-ceramics. In each of the proceeding, -quartz ss can be substantially absent from the crystalline phases. If present, -quartz ss can be less than about 20 wt % or, alternatively, less than about 15 wt % of the crystalline phases. Also Further crystalline phases might include spinel ss (e.g., hercynite and/or gahnite-hercynite ss), rutile, magnesium zinc phosphate, or spinel ss (e.g., hercynite and/or gahnite-hercynite ss) and rutile.

Disclosed herein are glass-ceramics having crystalline phases including -spodumene ss and either (i) pseudobrookite or (ii) vanadium or vanadium containing compounds so as to be colored and opaque glass-ceramics having coordinates, determined from total reflectancespecular includedmeasurements, in the CIELAB color space of the following ranges: L*=from about 20 to about 45; a*=from about 2 to about +2; and b*=from about 12 to about +1. Such CIELAB color space coordinates can be substantially uniform throughout the glass-ceramics. In each of the proceeding, -quartz ss can be substantially absent from the crystalline phases. If present, -quartz ss can be less than about 20 wt % or, alternatively, less than about 15 wt % of the crystalline phases. Also Further crystalline phases might include spinel ss (e.g., hercynite and/or gahnite-hercynite ss), rutile, magnesium zinc phosphate, or spinel ss (e.g., hercynite and/or gahnite-hercynite ss) and rutile.