The Furukawa Electric Co., Ltd.

Yukio Kohmura

Yoshinori Ishida

Toshihiro Mikami

Takashi Hibino

Yasuhiro Naka

Takuya Nishimoto

Masahide Kuwabara

Shinpei Todo

Hiroyuki Wada

Kiyoshi Arima

Akihiro Kanao

Koichi Toyosaki

Akira Nogami

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.

Porous preform vitrification apparatus

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.

Method of heating and processing an end of an optical fiber preform and apparatus for heating and processing an end of an optical fiber preform

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.

Apparatus and method for production of a porous optical fiber preform

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.

Optical fiber preform suspending and supporting apparatus and optical fiber preform processing apparatus

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. In particular, to accurately detect the phase angle, the high frequency current for generating the eddy current is changed by a low frequency of about 1/100th of the high frequency to change the average intensity and obtain at least two points of measurement defining the above phase angle. The electrical resistance of the hermetic coating is calculated from this phase angle. The electrical resistance shows the state of formation of the hermetic coating. The measurement value of the electrical resistance of the hermetic coating is used for setting the hermetic coating production conditions. The electroconductive film inspection method of the present invention may also be used for quality control etc. of thin films.

Production apparatus for producing an optical fiber cable

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. A gear fixed to the other end of the tray rotating shaft is in mesh with a ring gear on the upper end face of a hollow rotating member fixed to the upper surface of the rotor and located coaxially with the rotating shaft of the drive mechanism. As the rotor rotates, each tray is rotated by the tray rotating shaft gear-connected to the hollow rotating member, so that the wafer rotates around the tray rotating shaft. Accordingly, the speeds of rotation and revolution of the wafer can change independently of each other.

Vapor phase growth system and a gas-drive motor

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. In particular, to accurately detect the phase angle, the high frequency current for generating the eddy current is changed by a low frequency of about 1/100th of the high frequency to change the average intensity and obtain at least two points of measurement defining the above phase angle. The electrical resistance of the hermetic coating is calculated from this phase angle. The electrical resistance shows the state of formation of the hermetic coating. The measurement value of the electrical resistance of the hermetic coating is used for setting the hermetic coating production conditions. The electroconductive film inspection method of the present invention may also be used for quality control etc. of thin films.

Method and system for forming and inspecting an electroconductive film

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. In particular, to accurately detect the phase angle, the high frequency current for generating the eddy current is changes by a low frequency of about 1/100th of the high frequency to change the average intensity and obtain at least two points of measurement defining the above phase angle. The electrical resistance of the hermetic coating is calculated from this phase angle. The electrical resistance shows the state of formation of the hermetic coating. The measurement value of the electrical resistance of the hermetic coating is used for setting the hermetic coating production conditions. The electroconductive film inspection method of the present invention may also be used for quality control etc. of thin films.

Method and system for inspection of electroconductive film using eddy

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.

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Chiba, Japan

Yukio Kohmura