Abstract: A porous preform vitrification apparatus of the present invention, provided with a means for forcibly feeding nitrogen etc. from a furnace core tube to a discharge gas pipe so as to balance a pressure between a furnace core tube accommodating a porous preform and a heating furnace body surrounding this and so as to suppress pressure fluctuation in the furnace core tube to a minimum level, controlling the gas feed rate and discharge rate to the furnace core tube and the heating furnace body, and controlling the feed rate of the nitrogen from the furnace core tube to the discharge gas pipe based on a differential pressure signal of a pressure in the furnace core tube and a pressure in the heating furnace body.

Abstract: An end heating and processing method of an optical fiber preform. In this method, an optical fiber preform is processed by heating and melting an end of a vitrified optical fiber preform including a core portion and a cladding portion formed on an outer circumference thereof to process the end having a shape for drawing as an optical fiber.

Abstract: An apparatus for the production of a porous optical fiber preform preventing cracks in the preform and stabilizing quality over the longitudinal direction. The apparatus includes a reaction portion, a feed port for introducing a stream of gas, and a main exhaust port. A rotating mechanism is provided for mounting, rotating, and pulling up a seed rod for forming the porous optical fiber preform. A first burner emits a flame carrying fine particles of glass forming the core portion, and a second burner emits a flame carrying fine particles of glass forming the cladding portion. A portion adjusts the flow of the stream from the feed port to the main exhaust port so that the flames carrying the glass particles are not disturbed by the stream and so that the stream does not directly contact a fine glass particle deposit formed at a bottom end of the seed rod.

Abstract: An optical fiber preform suspending and supporting apparatus able to prevent deformation of a pin placed in a high temperature environment and able to support a porous optical fiber preform without adversely influencing supports of the pin and without causing inclination relative to the vertical line of a main shaft, wherein a movable connector is fitted into an enlarged-diameter portion of the lower end of a main shaft, this enlarged-diameter portion is connected with the movable connector by a pin so that the movable connector is able to swing around the pin, a holding portion including a supporting portion is formed integrally at the bottom of the movable connector to hold an enlarged-diameter portion of the upper end of a starting preform, and the diameter of the pin is in the range of 20% to 50% of the outside diameter of the enlarged-diameter portion of the lower end of the main shaft, and an optical fiber processing apparatus including the same.

Abstract: A method and apparatus for sintering a large-sized optical fiber preform without the occurrence of a large difference of diameters in a longitudinal direction, a non-solidified portion in a solidified portion of a porous soot body and a drop of the optical fiber preform. In response to a relative position of a sintering position of a porous soot body in an optical fiber preform to a sintering zone, in other words, in response to either of a lower end, an intermediate portion or an upper end of the optical fiber preform in the sintering zone, a controller controls at least one of a sintering temperature of an electric heater, a moving speed of the optical fiber preform and a supply gas flow supplying to the sintering zone.

Abstract: An optical fiber preform suspending and supporting apparatus able to prevent deformation of a pin placed in a high temperature environment and able to support a porous optical fiber preform without adversely influencing supports of the pin and without causing inclination relative to the vertical line of a main shaft, wherein a movable connector is fitted into an enlarged-diameter portion of the lower end of a main shaft, this enlarged-diameter portion is connected with the movable connector by a pin so that the movable connector is able to swing around the pin, a holding portion including a supporting portion is formed integrally at the bottom of the movable connector to hold an enlarged-diameter portion of the upper end of a starting preform, and the diameter of the pin is in the range of 20% to 50% of the outside diameter of the enlarged-diameter portion of the lower end of the main shaft, and an optical fiber processing apparatus including the same.

Abstract: A porous preform vitrification apparatus of the present invention, provided with a means for forcibly feeding nitrogen etc. from a furnace core tube to a discharge gas pipe so as to balance a pressure between a furnace core tube accommodating a porous preform and a heating furnace body surrounding this and so as to suppress pressure fluctuation in the furnace core tube to a minimum level, controlling the gas feed rate and discharge rate to the furnace core tube and the heating furnace body, and controlling the feed rate of the nitrogen from the furnace core tube to the discharge gas pipe based on a differential pressure signal of a pressure in the furnace core tube and a pressure in the heating furnace body.

Abstract: The present invention improves a tensile strength of an optical fiber obtained by heating to melt and drawing a preform and thereby realizes an extension of the surviving length of an optical fiber in a screening test. For this purpose, an optical fiber preform before the drawing step, that is, a preform (51), is stored while exposed to an ionized gas, that is, air (G), in a storage apparatus, and this stored preform (51) is conveyed while exposed to the ionized air (G) in the process of conveying this to a drawing use heating furnace, whereby deposition of foreign substances to the preform (51) is suppressed and a reduction of the tensile strength of the optical fiber due to the foreign substances can be prevented.

Abstract: An end heating and processing method of an optical fiber preform. In this method, an optical fiber preform is processed by heating and melting an end of a vitrified optical fiber preform including a core portion and a cladding portion formed on an outer circumference thereof to process the end having a shape for drawing as an optical fiber.

Abstract: An apparatus for accurately inspecting an electroconductive film using an eddy current and an apparatus for production of an optical fiber which measures on-line the electrical resistance, which shows the state of formation of the electroconductive hermetic coating of the optical fiber by an electroconductive film inspection method and reflects back the measurement results to the hermetic coating forming conditions. Optical fiber is made up of a core, a cladding, amorphous carbon film or other electroconductive hermetic coating formed on the outer surface of the cladding, and a protective coating. The electrical resistance of the hermetic coating generates an eddy current at the coating, the eddy current generated is detected, and the phase angle of the complex impedance is detected to enable calculation.

Abstract: A vapor phase growth system comprises a gas-drive motor including a ring-shaped stator and a rotor housed in a rotor chamber formed in the stator, and designed to rotate the rotor by injecting a gas toward gas receiving grooves in the peripheral surface of the rotor through injection ports which open in the peripheral surface of the rotor chamber. A rotating shaft of a susceptor rotating mechanism extends along the axis of a susceptor in a reactor, and has one end fixed to the top wall of the susceptor. A tray rotating shaft, having one end fixed to each of trays arranged individually in recesses in the outer surface of the susceptor, extends penetrating the peripheral wall of the susceptor. As a rotating shaft of a drive mechanism rotates, a wafer supported by each tray revolves around the rotating shaft.

Abstract: A method and system for accurately inspecting an electroconductive film using an eddy current and a process and apparatus for production of an optical fiber which measures on-line the electrical resistance, which shows the state of formation of the electroconductive hermetic coating of the optical fiber by the electroconductive film inspection method and reflects back the measurement results to the hermetic coating forming conditions. Optical fiber is made up of a core, a cladding, an amorphous carbon film or other electroconductive hermetic coating formed on the outer surface of the cladding, and a protective coating. The electrical resistance of the hermetic coating generates an eddy current at the coating, the eddy current generated is detected, and the phase angle of the complex impedance is detected to enable calculation.

Abstract: A method and system for accurately inspecting an electroconductive film using an eddy current and a process and apparatus for production of an optical fiber which measures on-line the electrical resistance, which shows the state of formation of the electroconductive hermetic coating of the optical fiber by the electroconductive film inspection method and reflects back the measurement results to the hermetic coating forming conditions are disclosed. Optical fiber is made up of a core, cladding, amorphous carbon film or other electroconductive hermetic coating formed on the outer surface of the cladding, and a protective coating. The electrical resistance of the hermetic coating generates an eddy current at the coating, the eddy current generated is detected, and the phase angle of the complex impedance is detected to enable calculation.

Abstract: An optical fiber soot synthesis apparatus which synthesizes around a fiber starting member forming a core of an optical fiber an optical fiber soot forming a cladding and which accurately calculates in real time the mass of the optical fiber soot when deposited so as to control the synthesis of the optical fiber soot. The optical fiber soot synthesis apparatus measures the weight of the rotating fiber starting member and optical fiber soot by a pair of soot weight detection sensors arranged at a fiber starting member support and rotational drive mechanisms divided so as to prevent the weight of the rotational drive mechanisms from having much of an effect. The computation and control apparatus performs operational processing from the measured weights and calculates the mass of only the optical fiber soot synthesized on the fiber starting member in real time. The computation and calculation apparatus refers to the calculated mass to control the synthesis of the optical fiber soot.

Abstract: With the method and apparatus for forming a thin film by plasma CVD according to this invention, a substrate is disposed between a pair of feed-gas supplying electrodes, and plasma is generated by applying a high frequency electric power to the substrate as an object to be processed. Feed gas is supplied from the feed-gas supplying electrodes into the plasma and is activated, whereby a film is formed on the substrate. Therefore, a solid and fine thin film which has corrosion-resistive and abrasion-resistive properties is formed on the substrate.