Abstract: A porcelain enamel substrate (1) mounts a light emitting element in which a porcelain enamel layer (5) is coated onto a surface of a core metal (4), and a reflective cup portion (7) that has a flat bottom surface and a sloping portion that surrounds this bottom surface is provided on a light emitting element mounting surface, and an electrode (6) for energizing a light emitting element (3) is provided on the light emitting element mounting surface, and the thickness of the electrode (6) within the reflective cup portion (7) is within a range of 5 ?m to 100 ?m.

Abstract: A porcelain enamel substrate mounts a light emitting device in which a porcelain enamel layer is coated onto a surface of a core metal, and a reflective cup portion that has a flat bottom surface and a sloping portion that surrounds this bottom surface is provided on a light emitting device mounting surface, and an electrode for energizing a light emitting device is provided on the light emitting device mounting surface, and the thickness of the electrode within the reflective cup portion is within a range of 5 ?m to 100 ?m.

Abstract: A drawing method for a bare optical fiber, comprises the steps of: melting an optical fiber preform using a heating device and drawing the bare optical fiber; and naturally cooling down the bare optical fiber or forcibly cooling down the bare optical fiber by a cooling device after the heating and melting step, wherein a temperature history during the drawing the optical fiber preform to obtain the bare optical fiber in the heating device satisfies a relational expression: T??0.01X+12 where a time period when the heated and molten portion of the optical fiber preform heated and molten by the heating device reaches 1800° C. or higher is T (min) and a OH group concentration in a cladding layer of the optical fiber preform is X (wtppm).

Abstract: A treatment method for an optical fiber including accommodating an optical fiber inside a treatment chamber; introducing a deuterium containing gas into the treatment chamber; and in a deuterium treatment step, exposing the optical fiber to atmosphere of the deuterium containing gas. In the deuterium treatment step, a deuterium concentration D in the treatment chamber during the deuterium treatment is calculated from an initial value A of a deuterium concentration in the deuterium containing gas inside the treatment chamber, a concentration B of oxygen in an ambient atmosphere of the treatment chamber, and a concentration C of oxygen in the deuterium containing gas inside the treatment chamber, and the deuterium concentration in the treatment chamber is controlled based on the deuterium concentration D calculated. Other gases such as hydrogen containing gas or nitrogen containing gas may also be used according to the invention.

Abstract: A method for manufacturing an optical fiber preform and an optical fiber preform apparatus are provided which can reduce hydroxyl groups in an optical fiber preform to a sufficient level without requiring any special equipment or operating conditions. When an optical fiber preform is manufactured by the vapor-phase deposition method, the dehydrating treatment is performed on a porous core preform that is obtained by deposing glass microparticles. In this treatment, a dehydrating agent is supplied to a dehydration apparatus through a feeding pipe and a main feeding pipe made of a material having a water permeance factor of 1.0×10?11 g·cm/cm2·s·cmHg or less, thereby manufacturing an optical fiber preform.